The Lumwana Copper Prospect in Zambia
- Authors: McGregor, James Archibald
- Date: 1965
- Subjects: Copper -- Zambia , Copper ores -- Zambia -- Analysis , Copper mines and mining -- Zambia , Mineralogy -- Zambia , Geology, Economic -- Zambia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5072 , http://hdl.handle.net/10962/d1013507
- Description: The Lumwana copper orebody is situated 170 miles west of the Copperbelt. It is stratiform and occurs in schists regarded as part of the Katanga System older than the lower-most Copperbelt quartzite. The discovery of copper at the Lumwana Prospect was a text book example of the success of the R.S.T. Mines Services Limited prospecting techniques. These include partial geochemical analyses of soil and drainage samples, pitting, drilling and radiometric, self potential, magnetic, resistivity and induced polarization methods of geophysical exploration. The copper-bearing formations at the Lumwana Prospect occur in the inverted limb of a great recumbent fold within the Mombezhi Dome. Three periods of folding are recognized from the study of regional foliations and lineation, and the attitude of fold elements in individual folds. Each period of folding is regarded as a major pulse in the Lufilian Orogeny. The first-formed folds are isoclinal and have axial planes which strike at 160°, and dip southwest at 15°; the plunge is 11° in a direction 212° . The formation of first folds was accompanied by thrust faulting and the development of nappe structures including the great Lumwana recumbent fold. The second folds have axial planes which strike at 170° and dip west at 44°, the plunge is 12° in a direction of 192°, and the folds tend to be overturned. The third folds cut across the earlier folds at variable angles, they are overturned to the north and have axial planes which dip gently to the south. The formation of third folds was such that northward-acting stress was rotated from southeast to southwest, and relaxation of this stress resulted in the development in competent strata of joints which strike at 120° and dip steeply. At the Lumwana Prospect the northward-acting Lufilian stress is thought to have been resolved into eastward acting stress during first and second folding as a result of compression near the centre of the Lufilian Arc. The third folds are the normal Lufilian folds sub-parallel to the Lufilian Arc. Normal faulting and intrusion of gabbro along planes of these faults and the earlier thrust faults eccurred in a post-Lufilian tensional phase. In recent times warping of the formations at Lumwana has occurred on east-west axes. Statistical examination of chemical data on fifty-four composite samples of mineralized rock from drill-holes reveals that the distribution of copper, iron and sulphur is related to that of potash and soda. These relationships can be explained on sedimentological grounds since the examination of the distribution of soda and potash in these and other horizons yields no evidence of metasomatism in the mineralized horizon. Intrusive into the mineralized schists, though not found in the ore, are thin amphibolites and a large serpentinite which contains relict olivine and bronzite. This is the first recorded occurrence of ultrabasic rocks in the Lower Roan Group of the Katanga System in this part of Zambia. Study of all formations at the Lumwana Prospect reveals that they have been metamorphosed in the epidote-amphibolite facies of regional metamorphism. Mineral assemblages indicative of the amphibolite facies are found in sheared rocks, and metamorphism in competent parts of the Upper Roan-Mwashia has been confined to the greenschist facies. Temperatures of metamorphism are estimated to have been between 250° and 280°C, and pressures are likely to have exceeded 6 kilobars. Evidence of metasomatism, absent in the Lower Roan, is found in the examination of the Upper Roan-Mwashia formations. Metasomatism includes scapolitization and albitization and is related to the intrusion of gabbro into these sediments, but does not necessarily involve exogenous material. The sulphide minerals identified are bornite, chalcocite, digenite, covellite, chalcopyrite, cubanite, valleriite, carrollite, pyrite and pyrrhotite. Intergrowths of these minerals have resulted from metamorphism at temperatures slightly in excess of 235°C. The copper sulphides are distributed zonally in the orebody with chalcocite- bornite ore where the mineralized schist is thin, and chalcopyrite- cubanite-pyrite ore where it is thick. Vertically the body contains horizons with sulphides relatively rich in copper at the top and bottom, and an intermediate zone with sulphides leaner in copper. This zonal distribution is considered to be evidence for syngenetic deposition of copper during successive cycles of transgression and regression. Ore genesis at Lumwana is closely related to genesis of the Copperbelt and Katanga orebodies. The Zambia-Katanga province is considered to have been enriched in copper epigenetically prior to the formation of the present-day orebodies. Reworking of these cupriferous rocks and some early-formed syngenetic deposits of which Lumwana is one, is considered to have played a major role in producing the present-day copper orebodies.
- Full Text:
- Authors: McGregor, James Archibald
- Date: 1965
- Subjects: Copper -- Zambia , Copper ores -- Zambia -- Analysis , Copper mines and mining -- Zambia , Mineralogy -- Zambia , Geology, Economic -- Zambia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5072 , http://hdl.handle.net/10962/d1013507
- Description: The Lumwana copper orebody is situated 170 miles west of the Copperbelt. It is stratiform and occurs in schists regarded as part of the Katanga System older than the lower-most Copperbelt quartzite. The discovery of copper at the Lumwana Prospect was a text book example of the success of the R.S.T. Mines Services Limited prospecting techniques. These include partial geochemical analyses of soil and drainage samples, pitting, drilling and radiometric, self potential, magnetic, resistivity and induced polarization methods of geophysical exploration. The copper-bearing formations at the Lumwana Prospect occur in the inverted limb of a great recumbent fold within the Mombezhi Dome. Three periods of folding are recognized from the study of regional foliations and lineation, and the attitude of fold elements in individual folds. Each period of folding is regarded as a major pulse in the Lufilian Orogeny. The first-formed folds are isoclinal and have axial planes which strike at 160°, and dip southwest at 15°; the plunge is 11° in a direction 212° . The formation of first folds was accompanied by thrust faulting and the development of nappe structures including the great Lumwana recumbent fold. The second folds have axial planes which strike at 170° and dip west at 44°, the plunge is 12° in a direction of 192°, and the folds tend to be overturned. The third folds cut across the earlier folds at variable angles, they are overturned to the north and have axial planes which dip gently to the south. The formation of third folds was such that northward-acting stress was rotated from southeast to southwest, and relaxation of this stress resulted in the development in competent strata of joints which strike at 120° and dip steeply. At the Lumwana Prospect the northward-acting Lufilian stress is thought to have been resolved into eastward acting stress during first and second folding as a result of compression near the centre of the Lufilian Arc. The third folds are the normal Lufilian folds sub-parallel to the Lufilian Arc. Normal faulting and intrusion of gabbro along planes of these faults and the earlier thrust faults eccurred in a post-Lufilian tensional phase. In recent times warping of the formations at Lumwana has occurred on east-west axes. Statistical examination of chemical data on fifty-four composite samples of mineralized rock from drill-holes reveals that the distribution of copper, iron and sulphur is related to that of potash and soda. These relationships can be explained on sedimentological grounds since the examination of the distribution of soda and potash in these and other horizons yields no evidence of metasomatism in the mineralized horizon. Intrusive into the mineralized schists, though not found in the ore, are thin amphibolites and a large serpentinite which contains relict olivine and bronzite. This is the first recorded occurrence of ultrabasic rocks in the Lower Roan Group of the Katanga System in this part of Zambia. Study of all formations at the Lumwana Prospect reveals that they have been metamorphosed in the epidote-amphibolite facies of regional metamorphism. Mineral assemblages indicative of the amphibolite facies are found in sheared rocks, and metamorphism in competent parts of the Upper Roan-Mwashia has been confined to the greenschist facies. Temperatures of metamorphism are estimated to have been between 250° and 280°C, and pressures are likely to have exceeded 6 kilobars. Evidence of metasomatism, absent in the Lower Roan, is found in the examination of the Upper Roan-Mwashia formations. Metasomatism includes scapolitization and albitization and is related to the intrusion of gabbro into these sediments, but does not necessarily involve exogenous material. The sulphide minerals identified are bornite, chalcocite, digenite, covellite, chalcopyrite, cubanite, valleriite, carrollite, pyrite and pyrrhotite. Intergrowths of these minerals have resulted from metamorphism at temperatures slightly in excess of 235°C. The copper sulphides are distributed zonally in the orebody with chalcocite- bornite ore where the mineralized schist is thin, and chalcopyrite- cubanite-pyrite ore where it is thick. Vertically the body contains horizons with sulphides relatively rich in copper at the top and bottom, and an intermediate zone with sulphides leaner in copper. This zonal distribution is considered to be evidence for syngenetic deposition of copper during successive cycles of transgression and regression. Ore genesis at Lumwana is closely related to genesis of the Copperbelt and Katanga orebodies. The Zambia-Katanga province is considered to have been enriched in copper epigenetically prior to the formation of the present-day orebodies. Reworking of these cupriferous rocks and some early-formed syngenetic deposits of which Lumwana is one, is considered to have played a major role in producing the present-day copper orebodies.
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The relationship between acquired resistance and transmission of Schistosoma Weinland, 1858, in man and its influences on the prevalence of S Capense (Harley, 1864) and S Mansoni Sambon, 1907, in Southern Rhodesia
- Authors: Clarke, H V de V
- Date: 1965
- Subjects: Platyhelminthes , Schistosoma , Schistosomiasis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5842 , http://hdl.handle.net/10962/d1010500 , Platyhelminthes , Schistosoma , Schistosomiasis
- Description: Bilharziasis ranks with Tuberculosis and Malaria as the three most important endemic diseases of man in Rhodesia. The prominence given to bilharziasis in the endemic diseases pattern arises from its high prevalence, particularly in the African population. It is probable that bilharziasis was endemic in the country even prior to the arrival in the conntry of the European settlers in 1890, but it was not until Orpen (1915) described the results of a small survey that local infections were proven. He reported 182 (31 percent) urinary infections in 592 African prisoners examined in the Salisbury gaol. In the ensuing 15 years there was only scanty evidence of the prevalence of the disease. However, in the decade 1931 to 1940 the Annual Public Health Reports of Southern Rhodesia indicated increasing prevalence, and this stimulated interest in the problem and led to the establishment in 1939 of a specialised laboratory to study the parasites causing the disease. The unpublished records of this laboratory indicate that in more recent years the disease has increased not only in prevalence but also in its intensity in infected individuals. Surveys show that the urinary form of the disease is more widespread than the intestinal form. Both forms are becoming more prevalent but the rapid increase of the latter, considered by most authorities to be the more severe, indicates that a greater importance must be accorded to it in the future. Introduction, p. 1.
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- Authors: Clarke, H V de V
- Date: 1965
- Subjects: Platyhelminthes , Schistosoma , Schistosomiasis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5842 , http://hdl.handle.net/10962/d1010500 , Platyhelminthes , Schistosoma , Schistosomiasis
- Description: Bilharziasis ranks with Tuberculosis and Malaria as the three most important endemic diseases of man in Rhodesia. The prominence given to bilharziasis in the endemic diseases pattern arises from its high prevalence, particularly in the African population. It is probable that bilharziasis was endemic in the country even prior to the arrival in the conntry of the European settlers in 1890, but it was not until Orpen (1915) described the results of a small survey that local infections were proven. He reported 182 (31 percent) urinary infections in 592 African prisoners examined in the Salisbury gaol. In the ensuing 15 years there was only scanty evidence of the prevalence of the disease. However, in the decade 1931 to 1940 the Annual Public Health Reports of Southern Rhodesia indicated increasing prevalence, and this stimulated interest in the problem and led to the establishment in 1939 of a specialised laboratory to study the parasites causing the disease. The unpublished records of this laboratory indicate that in more recent years the disease has increased not only in prevalence but also in its intensity in infected individuals. Surveys show that the urinary form of the disease is more widespread than the intestinal form. Both forms are becoming more prevalent but the rapid increase of the latter, considered by most authorities to be the more severe, indicates that a greater importance must be accorded to it in the future. Introduction, p. 1.
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Xhosa-English pronunciation in the south-east Cape
- Authors: Hundleby, C E
- Date: 1965
- Subjects: Xhosa language -- Pronunciation by foreign speakers English language -- Pronunciation by foreign speakers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2303 , http://hdl.handle.net/10962/d1012467
- Description: The thesis mainly concerns itself with an analysis of the present day pronunciation of Xhosa-English. The isolation and identification of the segmental phonemes and the phonemes of stress, intonation and transition form the core of the work. The author has attempted to give continuity by introducing a subsidiary theme, the Lado hypothesis as stated on page 1. In conformity with the the methodology imposed by the Lado formula, it was first necessary to establish two things: first, a standard background against which the characteristics of XEP could be compared, and secondly, to give briefly, but in sufficient detail for our purpose, the main phonological features of the mother tongue.
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- Authors: Hundleby, C E
- Date: 1965
- Subjects: Xhosa language -- Pronunciation by foreign speakers English language -- Pronunciation by foreign speakers
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2303 , http://hdl.handle.net/10962/d1012467
- Description: The thesis mainly concerns itself with an analysis of the present day pronunciation of Xhosa-English. The isolation and identification of the segmental phonemes and the phonemes of stress, intonation and transition form the core of the work. The author has attempted to give continuity by introducing a subsidiary theme, the Lado hypothesis as stated on page 1. In conformity with the the methodology imposed by the Lado formula, it was first necessary to establish two things: first, a standard background against which the characteristics of XEP could be compared, and secondly, to give briefly, but in sufficient detail for our purpose, the main phonological features of the mother tongue.
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The dramatic theory of William Hazlitt : "Imagination in criticism"
- Authors: De Villiers, André
- Date: 1964
- Subjects: Hazlitt, William, 1778-1830 , Drama -- History and criticism -- 19th century , English drama -- History and criticism -- 19th century
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2320 , http://hdl.handle.net/10962/d1013383
- Full Text:
- Authors: De Villiers, André
- Date: 1964
- Subjects: Hazlitt, William, 1778-1830 , Drama -- History and criticism -- 19th century , English drama -- History and criticism -- 19th century
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2320 , http://hdl.handle.net/10962/d1013383
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Between Renaissance and Baroque: a study of the keybord works of Frescobaldi
- Authors: Maske, H H
- Date: 1963
- Subjects: Frescobaldi, Girolamo,1583-1643 -- Keyboard instrument music , Frescobaldi, Girolamo, 1583-1643 -- Criticism and interpretation , Music -- Italy -- 17th century , Organ music -- History and criticism , Keyboard instrument music -- 17th century -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2686 , http://hdl.handle.net/10962/d1012841
- Description: The present study is an attempt to enlarge upon the proposition that the age of Frescobaldi was, like all others, an age of transition, in his case the transition from Renaissance to Baroque. His position within this change is central, both in time and importance. In our first two chapters, the various categories of keyboard works which he enriched will be considered, with their prehistories, his contributions, and analyses of individual pieces. In chapter I the works mainly of instrumental origin will be dealt with, and in chapter ll those of more vocal derivation. In the final chapter, the information thus gleaned will be used to demonstrate his exact position within the transition, particularly with regard to its two most important aspects, the harmonic field and the interaction of vocal and instrumental elements.
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- Authors: Maske, H H
- Date: 1963
- Subjects: Frescobaldi, Girolamo,1583-1643 -- Keyboard instrument music , Frescobaldi, Girolamo, 1583-1643 -- Criticism and interpretation , Music -- Italy -- 17th century , Organ music -- History and criticism , Keyboard instrument music -- 17th century -- History and criticism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2686 , http://hdl.handle.net/10962/d1012841
- Description: The present study is an attempt to enlarge upon the proposition that the age of Frescobaldi was, like all others, an age of transition, in his case the transition from Renaissance to Baroque. His position within this change is central, both in time and importance. In our first two chapters, the various categories of keyboard works which he enriched will be considered, with their prehistories, his contributions, and analyses of individual pieces. In chapter I the works mainly of instrumental origin will be dealt with, and in chapter ll those of more vocal derivation. In the final chapter, the information thus gleaned will be used to demonstrate his exact position within the transition, particularly with regard to its two most important aspects, the harmonic field and the interaction of vocal and instrumental elements.
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Prototypes of black wattle tannins and their stereochemistry
- Authors: Drewes, Siegfried Ernst
- Date: 1963
- Subjects: Tannins -- Anthocyanidis Stereochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4460 , http://hdl.handle.net/10962/d1011437
- Description: A number of interrelated flavonoid compounds, present in trace quantities in mature black wattle (Acacia mearnsii De Wild) bark, have been isolated and identified for the first time. They include a) the resorcinol-pyrogallol analogues, (+)-leuco-robinetinidin (7,5',4',5'-tetrahydroxyflavan-3,4-diol), dihydrorobinetin (7,5',4',5'-tetrahydroxyflavan-3-ol-4-one) and robtein (2',4',5,4,5- pentahydroxychalcone) and b) the resorcinol-catechol analogues, (+)-leuco-fisetinidin (7,3',4'-trihydroxyflavan-3,4-diol), fustin (7,3',4'-trihydroxyflavan-3-ol-4-one), (-)-fisetinidol (7,3',4'trihydroxyflavan- 3-ol), butein (2',4',3,4-tetrahydroxychalcone) and butin (7,5',4'-trihydroxyflavan-4-one). In addition, two flavonol glycosides, myricitrin (3,5,7,3',4',5'-hexahydroxyflavone-3-rhamnoside ) and quercitrin (5,5,7,5',4'-pentahydroxyflavone-3-rhamnoside), which belong to the phloroglucinol-pyrogallol and phloroglucinolcatechol class of flavonoids respectively, were isolated from immature bark. These represent the only glycosides isolated hitherto from wattle bark or heartwood extracts. Summary, p. i.
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- Authors: Drewes, Siegfried Ernst
- Date: 1963
- Subjects: Tannins -- Anthocyanidis Stereochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4460 , http://hdl.handle.net/10962/d1011437
- Description: A number of interrelated flavonoid compounds, present in trace quantities in mature black wattle (Acacia mearnsii De Wild) bark, have been isolated and identified for the first time. They include a) the resorcinol-pyrogallol analogues, (+)-leuco-robinetinidin (7,5',4',5'-tetrahydroxyflavan-3,4-diol), dihydrorobinetin (7,5',4',5'-tetrahydroxyflavan-3-ol-4-one) and robtein (2',4',5,4,5- pentahydroxychalcone) and b) the resorcinol-catechol analogues, (+)-leuco-fisetinidin (7,3',4'-trihydroxyflavan-3,4-diol), fustin (7,3',4'-trihydroxyflavan-3-ol-4-one), (-)-fisetinidol (7,3',4'trihydroxyflavan- 3-ol), butein (2',4',3,4-tetrahydroxychalcone) and butin (7,5',4'-trihydroxyflavan-4-one). In addition, two flavonol glycosides, myricitrin (3,5,7,3',4',5'-hexahydroxyflavone-3-rhamnoside ) and quercitrin (5,5,7,5',4'-pentahydroxyflavone-3-rhamnoside), which belong to the phloroglucinol-pyrogallol and phloroglucinolcatechol class of flavonoids respectively, were isolated from immature bark. These represent the only glycosides isolated hitherto from wattle bark or heartwood extracts. Summary, p. i.
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The influence of temperature in the ecology of the intermediate host snails of Schistosoma and Fasciola (Trematoda) in southern Rhodesia
- Authors: Shiff, Clive Julian
- Date: 1963
- Subjects: Schistosoma , Schistosomiasis , Fasciola , Snails -- Zimbabwe , Trematoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5881 , http://hdl.handle.net/10962/d1013208
- Description: The influence of temperature on the bionomics of Bulinus (Physopsis) globosus, Biomphalaria pfeifferi and Lymnaea natalensis has been studied both in the laboratory under controlled conditions and in the field under normal seasonal influences. Field studies were carried out in two different localities, one a semi-permanent pond and the other a temporary waterbody. For this purpose a sampling implement was developed. The results show the seasonal progression of these populations both with respect to estimated numbers and the size distribution of the snails. The rate of actual increase at different seasons was calculated for the three species where the data were sufficient. In the laboratory the snails were maintained at various temperatures, other conditions being kept standard. Daily records of mortality and fecundity of various cohorts reared from the egg stage enabled the compilation of life tables fof the speciesand from these data were calcualted the intrinsic rate of natural increase and other parameters. Effects of crowding in aquaria were studied. From the data obtained in the laboratory it was possible to predict the distribution and population potential for each species for snail of various environmental conditions. These predictions were, in fact, confirmed by field observation.
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- Authors: Shiff, Clive Julian
- Date: 1963
- Subjects: Schistosoma , Schistosomiasis , Fasciola , Snails -- Zimbabwe , Trematoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5881 , http://hdl.handle.net/10962/d1013208
- Description: The influence of temperature on the bionomics of Bulinus (Physopsis) globosus, Biomphalaria pfeifferi and Lymnaea natalensis has been studied both in the laboratory under controlled conditions and in the field under normal seasonal influences. Field studies were carried out in two different localities, one a semi-permanent pond and the other a temporary waterbody. For this purpose a sampling implement was developed. The results show the seasonal progression of these populations both with respect to estimated numbers and the size distribution of the snails. The rate of actual increase at different seasons was calculated for the three species where the data were sufficient. In the laboratory the snails were maintained at various temperatures, other conditions being kept standard. Daily records of mortality and fecundity of various cohorts reared from the egg stage enabled the compilation of life tables fof the speciesand from these data were calcualted the intrinsic rate of natural increase and other parameters. Effects of crowding in aquaria were studied. From the data obtained in the laboratory it was possible to predict the distribution and population potential for each species for snail of various environmental conditions. These predictions were, in fact, confirmed by field observation.
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A comparative study of the catechin components in the barks of wattle species related to Acacia Mernsii
- Authors: Maihs, Edwin Alfred
- Date: 1962
- Subjects: Wattles (Plants) Acacia mearnsii Acacia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4482 , http://hdl.handle.net/10962/d1012793
- Description: The distribution of flavonoid constituents in the barks of Acacia mearnsii De Wild.(black wattle) , A· decurens Willd. (green wattle), A. dealbata Link.(silver wattle) and A. pycnantha Benth.(golden wattle) has been studied. Bark extracts of the four wattle species have been fractionated into low molecular weight fractions containing mainly catechins and other low molecular weight constituents, and high molecular weight fractions containing the bulk of the polymerized tannins. The low molecular weight fractions have been further fractionated by "preparative paper chromatography". (-)-Robinetinidol, (-)-7:3': 4': 5'-tetrahydroxy flavan- 3-ol, a new naturally occurring catechin, (+)-catechin and (+)-gallocatechin have been isolated from the barks of A. mearnsii, A. dealbata and A. pycnantha. (-)-Epicatechin and (-)-epigallocatechin have been identified in the bark extracts of A. dealbata and A. pycnantha, but appeared to be absent in the barks of A. mearnsii and A. decurrens. (-)-Epicatechin has been isolated fron A. dealbata, and both (-}-epicatechin and (-)-epigallocatechin were isolated from A. pycnantha. (-)-Epicatechin gallate, (-)-epigallocatechin gallate and gallic acid were isolated from A. pycnantha only. These three constituents appeared to be absent in the barks of the three other wattle species. (-)-Epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate which were not available for direct comparison, were subsequently isolated from green tea where they are present as major phenolic constituents. A method for the quantitative estimation of polyphenolic substances on two dimensional paper chromatograms has been developed, and a photoelectric densitometer constructed. Two spray reagents, ammoniacal silver nitrate and bisdiazotised benzidine, were found to give straight line relationships of instrument deflection against log concentration for flavonoid substances. This estimation method for the first time supplied means for a detailed study of the concentration of catechin constituents in the bark extracts of A. mearnsii, A. decurrens, A. dealbata, A. pycnantha and of A. mearnsii x A. decurrens hybrids. The concentration of catechin constituents has been shown to vary considerably between species whereas variation within species was small. In the latter respect silver wattle is an exception. Taxonomic significance may possibly be attached to the distribution of catechin constituents in the bark of the four Acacia species. The concentration of (-)-robinetinidol, which appears to be the characteristic compound of these Acacias, progressively decreases in the sequence black-, black x green hybrid, green-, silver- and golden wattle, while the number of catechin constituents of the "phloroglucinol series" increases in the same sequence. It thus appears, that by the examination of their bark components, a differentiation between species of a subgenera may be possible. Two tannins, constituents D and B, which are related to the leuco-anthocyanidins (flavan-3:4-diols) have been found in the barks of the four wattle species. One of the two, constituent D, was isolated in a pure form from the barks of A. mearnsii and A. pycnantha. Constituent D was found to generate robinetinidin and an orange pigment, the structure of which has not yet been fully identified. Compound D and its acetyl- and methoxyl derivatives did not crystallize. From the results of alkaline-, acidic- and enzymatic degradations, colour reactions and light-absorption studies, combustion analysis of the compound and its derivatives and molecular weight estimations, constituent D is surmised to be a dimer of 7:3': 4': 5'-tetrahydroxyflavan-3:4-diol (leuco-robinetinidin), The isolation of this complex leuco-anthocyanidin tannin represents the first isolation of a flavonoid tannin from commercial vegetable tannin sources. The second tannin obtained from the bark of A.mearnsii, "constituent B" appears to consist of two overlapping substances, which have not yet been separated. The tannin (B) was found to have an average molecular weight of 676 and it is considered likely that both substances may be dimolecular. On heating with mineral acid robinetinidin, fisetinidin and an orange pigment are generated, the pigment being identical with the pigment generated from constituent D. It may therefore be assumed that "Constituent B" consists of a mixture of complex leuco-robinetinidins and leucofisetinidins. The distribution of complex leuco-anthocyanidins in the bark extracts of Acacia mearnsii, A. decurrens, A. dealbata and A. pycnantha has been examined. A correlation between the distribution of leuco-anthocyanidins in the bark of the four wattle species, and accepted systematics, does not, apparently, exist.
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- Authors: Maihs, Edwin Alfred
- Date: 1962
- Subjects: Wattles (Plants) Acacia mearnsii Acacia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4482 , http://hdl.handle.net/10962/d1012793
- Description: The distribution of flavonoid constituents in the barks of Acacia mearnsii De Wild.(black wattle) , A· decurens Willd. (green wattle), A. dealbata Link.(silver wattle) and A. pycnantha Benth.(golden wattle) has been studied. Bark extracts of the four wattle species have been fractionated into low molecular weight fractions containing mainly catechins and other low molecular weight constituents, and high molecular weight fractions containing the bulk of the polymerized tannins. The low molecular weight fractions have been further fractionated by "preparative paper chromatography". (-)-Robinetinidol, (-)-7:3': 4': 5'-tetrahydroxy flavan- 3-ol, a new naturally occurring catechin, (+)-catechin and (+)-gallocatechin have been isolated from the barks of A. mearnsii, A. dealbata and A. pycnantha. (-)-Epicatechin and (-)-epigallocatechin have been identified in the bark extracts of A. dealbata and A. pycnantha, but appeared to be absent in the barks of A. mearnsii and A. decurrens. (-)-Epicatechin has been isolated fron A. dealbata, and both (-}-epicatechin and (-)-epigallocatechin were isolated from A. pycnantha. (-)-Epicatechin gallate, (-)-epigallocatechin gallate and gallic acid were isolated from A. pycnantha only. These three constituents appeared to be absent in the barks of the three other wattle species. (-)-Epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate which were not available for direct comparison, were subsequently isolated from green tea where they are present as major phenolic constituents. A method for the quantitative estimation of polyphenolic substances on two dimensional paper chromatograms has been developed, and a photoelectric densitometer constructed. Two spray reagents, ammoniacal silver nitrate and bisdiazotised benzidine, were found to give straight line relationships of instrument deflection against log concentration for flavonoid substances. This estimation method for the first time supplied means for a detailed study of the concentration of catechin constituents in the bark extracts of A. mearnsii, A. decurrens, A. dealbata, A. pycnantha and of A. mearnsii x A. decurrens hybrids. The concentration of catechin constituents has been shown to vary considerably between species whereas variation within species was small. In the latter respect silver wattle is an exception. Taxonomic significance may possibly be attached to the distribution of catechin constituents in the bark of the four Acacia species. The concentration of (-)-robinetinidol, which appears to be the characteristic compound of these Acacias, progressively decreases in the sequence black-, black x green hybrid, green-, silver- and golden wattle, while the number of catechin constituents of the "phloroglucinol series" increases in the same sequence. It thus appears, that by the examination of their bark components, a differentiation between species of a subgenera may be possible. Two tannins, constituents D and B, which are related to the leuco-anthocyanidins (flavan-3:4-diols) have been found in the barks of the four wattle species. One of the two, constituent D, was isolated in a pure form from the barks of A. mearnsii and A. pycnantha. Constituent D was found to generate robinetinidin and an orange pigment, the structure of which has not yet been fully identified. Compound D and its acetyl- and methoxyl derivatives did not crystallize. From the results of alkaline-, acidic- and enzymatic degradations, colour reactions and light-absorption studies, combustion analysis of the compound and its derivatives and molecular weight estimations, constituent D is surmised to be a dimer of 7:3': 4': 5'-tetrahydroxyflavan-3:4-diol (leuco-robinetinidin), The isolation of this complex leuco-anthocyanidin tannin represents the first isolation of a flavonoid tannin from commercial vegetable tannin sources. The second tannin obtained from the bark of A.mearnsii, "constituent B" appears to consist of two overlapping substances, which have not yet been separated. The tannin (B) was found to have an average molecular weight of 676 and it is considered likely that both substances may be dimolecular. On heating with mineral acid robinetinidin, fisetinidin and an orange pigment are generated, the pigment being identical with the pigment generated from constituent D. It may therefore be assumed that "Constituent B" consists of a mixture of complex leuco-robinetinidins and leucofisetinidins. The distribution of complex leuco-anthocyanidins in the bark extracts of Acacia mearnsii, A. decurrens, A. dealbata and A. pycnantha has been examined. A correlation between the distribution of leuco-anthocyanidins in the bark of the four wattle species, and accepted systematics, does not, apparently, exist.
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An investigation into the effects of ant control on scale insect populations (Homoptera, Coccoidea) of citrus trees in the Eastern Cape Province, South Africa
- Authors: Brettell, J H
- Date: 1962
- Subjects: Scale insects -- South Africa Insect pests -- Biological control
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5838 , http://hdl.handle.net/10962/d1009700
- Description: In order that the citrus industry in South Africa may be commercially developed to the greatest possible extent it is of importance that certain basic ecological problems should be investigated. Until the complex relationships between the host plant, the insect pests and their parasites and predators are known, the results of applications of either chemical or biological control must be largely a matter of chance. A certain amount of rather generalised work in this connection has already been done in South Africa, principally by Carnegie (1955), Smithers (1953) and Whitehead (1948) in the Eastern Cape Province and by Steyn (1954) in the Transvaal. The first three of these workers were content to determine which species of insects occurred in citrus orchards and made some attempts to study the biology of certain predators. Steyn went a little further when he correlated ant activity with scale insect infestations. Without doubt the most economically important insect pests of citrus are the scale insects (Homoptera: Coccoidea). Introduction, p. 1.
- Full Text:
- Authors: Brettell, J H
- Date: 1962
- Subjects: Scale insects -- South Africa Insect pests -- Biological control
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5838 , http://hdl.handle.net/10962/d1009700
- Description: In order that the citrus industry in South Africa may be commercially developed to the greatest possible extent it is of importance that certain basic ecological problems should be investigated. Until the complex relationships between the host plant, the insect pests and their parasites and predators are known, the results of applications of either chemical or biological control must be largely a matter of chance. A certain amount of rather generalised work in this connection has already been done in South Africa, principally by Carnegie (1955), Smithers (1953) and Whitehead (1948) in the Eastern Cape Province and by Steyn (1954) in the Transvaal. The first three of these workers were content to determine which species of insects occurred in citrus orchards and made some attempts to study the biology of certain predators. Steyn went a little further when he correlated ant activity with scale insect infestations. Without doubt the most economically important insect pests of citrus are the scale insects (Homoptera: Coccoidea). Introduction, p. 1.
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Construction of a wide-frequency range double heterodyne conductance bridge and its use in the investigation of polarisation errors in conductance measurements
- Authors: Govinden, Herby Silvester
- Date: 1961
- Subjects: Electrodynamics Electrolytes -- Conductivity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5522 , http://hdl.handle.net/10962/d1012074
- Description: (1) Developments in a.c. conductance techniques during the past ninety years have been reviewed, and a brief outline is given of the older theories regarding electrolytic polarisation. (2) A conductance bridge - incorporating the double heterodyne principle - has been constructed, capable of giving resistance readings to an accuracy of 0.01% over a range of frequencies covering the best part of 100 kc/s. It has also been found possible to calibrate the oscillator so that frequency settings can be guaranteed to an accuracy of , at least, 0.1% in the range: 2 kc/S to 50 kc/S. (3) The Wheatstone Bridge Network has been slightly modified to enable measurements at the high frequencies. (4) Resistances in the measuring arm of the bridge have been calibrated 'in situ' by the method of intercomparison. (5) A brief description is given of the modern theories regarding electrode processes and modern methods of eliminating electrode effects. (6) Two types of conductance cells, with bright Pt electrodes, have been used to carry out measurements on potassium chloride solutions: (a) Thomas- Gledhill Cell (b) Nichol-Fuoss Cell. The latter incorporates concentric, cylindrical electrodes with the lead to the outer electrode acting as an electrical shield for the lead to the inner electrode. This cell was constructed and used for the first time in this laboratory. (7) From resistance-frequency graphs plotted, it is shown that the Jones and Christian extrapolation procedure cannot be applied (with any degree of confidence) to obtain the true resistance, when measurements are effected over an extended range of frequencies. (8) The method of resistance-reactance diagrams is discussed and applied to various networks of resistances and capacitances. (9) By drawing resistance-reactance diagrams for the experimental readings obtained, equivalent circuits have been derived - for all the solutions investigated in the N-F cell, and for the approx. O.OlD solution in the T-G cell - which approximate to cell behaviour in the range: 500 c/s to 75 kc/s. The less concentrated solutions in the T-G cell show peculiar behaviour at the high frequencies. (10) Probable reasons are advanced for deviations from linearity on resistance-frequency graphs. (11) A new method is proposed for determining the true resistance of solutions measured in cells of the N-F type. Summary, p. 166-167.
- Full Text:
- Authors: Govinden, Herby Silvester
- Date: 1961
- Subjects: Electrodynamics Electrolytes -- Conductivity
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5522 , http://hdl.handle.net/10962/d1012074
- Description: (1) Developments in a.c. conductance techniques during the past ninety years have been reviewed, and a brief outline is given of the older theories regarding electrolytic polarisation. (2) A conductance bridge - incorporating the double heterodyne principle - has been constructed, capable of giving resistance readings to an accuracy of 0.01% over a range of frequencies covering the best part of 100 kc/s. It has also been found possible to calibrate the oscillator so that frequency settings can be guaranteed to an accuracy of , at least, 0.1% in the range: 2 kc/S to 50 kc/S. (3) The Wheatstone Bridge Network has been slightly modified to enable measurements at the high frequencies. (4) Resistances in the measuring arm of the bridge have been calibrated 'in situ' by the method of intercomparison. (5) A brief description is given of the modern theories regarding electrode processes and modern methods of eliminating electrode effects. (6) Two types of conductance cells, with bright Pt electrodes, have been used to carry out measurements on potassium chloride solutions: (a) Thomas- Gledhill Cell (b) Nichol-Fuoss Cell. The latter incorporates concentric, cylindrical electrodes with the lead to the outer electrode acting as an electrical shield for the lead to the inner electrode. This cell was constructed and used for the first time in this laboratory. (7) From resistance-frequency graphs plotted, it is shown that the Jones and Christian extrapolation procedure cannot be applied (with any degree of confidence) to obtain the true resistance, when measurements are effected over an extended range of frequencies. (8) The method of resistance-reactance diagrams is discussed and applied to various networks of resistances and capacitances. (9) By drawing resistance-reactance diagrams for the experimental readings obtained, equivalent circuits have been derived - for all the solutions investigated in the N-F cell, and for the approx. O.OlD solution in the T-G cell - which approximate to cell behaviour in the range: 500 c/s to 75 kc/s. The less concentrated solutions in the T-G cell show peculiar behaviour at the high frequencies. (10) Probable reasons are advanced for deviations from linearity on resistance-frequency graphs. (11) A new method is proposed for determining the true resistance of solutions measured in cells of the N-F type. Summary, p. 166-167.
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Gold fineness in hydrothermal ores : an investigation into the distribution of gold and silver in Southern Rhodesian gold ores
- Authors: Eales, Hugh V
- Date: 1961
- Subjects: Hydrothermal deposits -- Zimbabwe , Gold ores -- Zimbabwe , Silver ores -- Zimbabwe , Silver mines and mining -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5077 , http://hdl.handle.net/10962/d1014887
- Description: This investigation is concerned with primary variations in the silver content of gold which occurs in hydrothermal deposits, particularly those of hypothermal character which are found in Basement rocks in Southern Rhodesia. The nature of the gold produced by a number of different mines has been studied by reference to production data, and microscope techniques as well as gold and silver assays have been used to determine and to explain the variations in gold fineness. The literature does not contain a great deal of information which is relevant to this topic, but an attempt has been made here to summarize the more important contributions by different writers. From this it emerges that the interpretations given by different investigators are in conflict and that paradoxes may arise when efforts are made to explain observed variations in fineness in terms of certain generalizations which have become entrenched in the literaure. In particular, it is shown that falling temperature alone cannot account for the occurrence of silver-rich gold in certain deposits. The Gwanda district of Southern Rhodesia has been selected as a typical gold belt, and the variation in fineness in 150 producers is described. The deposits are hypothermal in character, and the average fineness of the gold is high but variable, but in a small proportion the fineness is low. It is shown that the nature of the host rock and the distance of a deposit from the granite contact appear to have no influence on the fineness of the gold and that there is no zonal arrangement of fineness values. There is a suggestion that diversity of mineral species in any particular area may be accompanied by rather wide fluctuations in the gold fineness. The variations of fineness in eight typical Southern Rhodesian deposits are studied in detail, by analysis of production data, by assaying specimens of the ore and by the examination of polished specimens of gold-bearing ore. Briefer reference is made to two other deposits in the territory, and to deposits in other countries which appear to bear out the conclusions reached in this section. It emerges that there are two factors which can commonly be correlated with variations in fineness. The first of these is the grade of the ore: high-grade ore generally contains purer gold than low-grade ore. Secondly, the textural evidence indicates that gold which separates relatively early in the paragenesis contains more silver than that which is deposited in the final stages of metallization. A general survey which draws on the literature as well as on the writer's examinations of deposits in the territory indicates that, in general, gold which is associated with late-stage minerals such as tellurides, antimony, bismuth and bismuthinite is silver-poor. Gold associated with galena may be either silver-rich or silver-poor, whereas gold which is of the same age as chalcopyrite or sphalerite is very frequently rich in silver. The difficulty which is encountered in establishing the age of gold which is intimately associated with pyrite and arsenopyrite renders uncertain the correlation between fineness and age of gold in these latter cases. There are, however, indications that gold which is truly contemporaneous with either pyrite or arsenopyrite is silver-rich. In the discussion, the objections to the common practice of singling out temperature as the most potent factor controlling gold fineness are listed. Chief amongst these objections is the fact that gold does not in all deposits increase in fineness with increasing depth: examples are quoted where fineness was found to decrease as deeper levels of the ore body were exploited. It is shown that there is no consistent relationship between the size of gold grains and their silver content. It is the writer's conclusion that in hydrothermal deposits in this territory the high fineness of the gold is due to increasing solubility of silver in the ore fluids in the late states, and that where hydrothermal deposits are characterized by gold with low average fineness, an unusually large proportion of the gold has been deposited early in the paragenotic sequence. In the majority of hypothermal deposits, however, the bulk of tho gold separates late in the sequence and the fineness is accordingly high. It is believed that the relationship which exists between fineness and tenor in many deposits is due to protracted crystallization of gold in those portions of the ore body which remained permeable to the latest stages. These portions of the ore body, which represent either valuable ore shoots or ore shoots in miniature, are likely to contain gold of variable character, but the average silver content will be low because a large proportion of the gold is "late" gold. The factors which might cause epithermal gold to have a lower fineness than mesothermal or hypothermal gold are briefly discussed. Some possible applications of this study are indicated in the final chapter. It is claimed that records of gold fineness might constitute a valuable addition to mill records. Tentative suggestions are made regarding a method whereby the approaching exhaustion of a deposit might in some cases be predicted. With regard to the origin of the gold in the Witwatersrand sediments, it is pointed out that the modified placer hypothesis is not fully equipped to explain certain of the variations in the composition of the gold.
- Full Text:
- Authors: Eales, Hugh V
- Date: 1961
- Subjects: Hydrothermal deposits -- Zimbabwe , Gold ores -- Zimbabwe , Silver ores -- Zimbabwe , Silver mines and mining -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5077 , http://hdl.handle.net/10962/d1014887
- Description: This investigation is concerned with primary variations in the silver content of gold which occurs in hydrothermal deposits, particularly those of hypothermal character which are found in Basement rocks in Southern Rhodesia. The nature of the gold produced by a number of different mines has been studied by reference to production data, and microscope techniques as well as gold and silver assays have been used to determine and to explain the variations in gold fineness. The literature does not contain a great deal of information which is relevant to this topic, but an attempt has been made here to summarize the more important contributions by different writers. From this it emerges that the interpretations given by different investigators are in conflict and that paradoxes may arise when efforts are made to explain observed variations in fineness in terms of certain generalizations which have become entrenched in the literaure. In particular, it is shown that falling temperature alone cannot account for the occurrence of silver-rich gold in certain deposits. The Gwanda district of Southern Rhodesia has been selected as a typical gold belt, and the variation in fineness in 150 producers is described. The deposits are hypothermal in character, and the average fineness of the gold is high but variable, but in a small proportion the fineness is low. It is shown that the nature of the host rock and the distance of a deposit from the granite contact appear to have no influence on the fineness of the gold and that there is no zonal arrangement of fineness values. There is a suggestion that diversity of mineral species in any particular area may be accompanied by rather wide fluctuations in the gold fineness. The variations of fineness in eight typical Southern Rhodesian deposits are studied in detail, by analysis of production data, by assaying specimens of the ore and by the examination of polished specimens of gold-bearing ore. Briefer reference is made to two other deposits in the territory, and to deposits in other countries which appear to bear out the conclusions reached in this section. It emerges that there are two factors which can commonly be correlated with variations in fineness. The first of these is the grade of the ore: high-grade ore generally contains purer gold than low-grade ore. Secondly, the textural evidence indicates that gold which separates relatively early in the paragenesis contains more silver than that which is deposited in the final stages of metallization. A general survey which draws on the literature as well as on the writer's examinations of deposits in the territory indicates that, in general, gold which is associated with late-stage minerals such as tellurides, antimony, bismuth and bismuthinite is silver-poor. Gold associated with galena may be either silver-rich or silver-poor, whereas gold which is of the same age as chalcopyrite or sphalerite is very frequently rich in silver. The difficulty which is encountered in establishing the age of gold which is intimately associated with pyrite and arsenopyrite renders uncertain the correlation between fineness and age of gold in these latter cases. There are, however, indications that gold which is truly contemporaneous with either pyrite or arsenopyrite is silver-rich. In the discussion, the objections to the common practice of singling out temperature as the most potent factor controlling gold fineness are listed. Chief amongst these objections is the fact that gold does not in all deposits increase in fineness with increasing depth: examples are quoted where fineness was found to decrease as deeper levels of the ore body were exploited. It is shown that there is no consistent relationship between the size of gold grains and their silver content. It is the writer's conclusion that in hydrothermal deposits in this territory the high fineness of the gold is due to increasing solubility of silver in the ore fluids in the late states, and that where hydrothermal deposits are characterized by gold with low average fineness, an unusually large proportion of the gold has been deposited early in the paragenotic sequence. In the majority of hypothermal deposits, however, the bulk of tho gold separates late in the sequence and the fineness is accordingly high. It is believed that the relationship which exists between fineness and tenor in many deposits is due to protracted crystallization of gold in those portions of the ore body which remained permeable to the latest stages. These portions of the ore body, which represent either valuable ore shoots or ore shoots in miniature, are likely to contain gold of variable character, but the average silver content will be low because a large proportion of the gold is "late" gold. The factors which might cause epithermal gold to have a lower fineness than mesothermal or hypothermal gold are briefly discussed. Some possible applications of this study are indicated in the final chapter. It is claimed that records of gold fineness might constitute a valuable addition to mill records. Tentative suggestions are made regarding a method whereby the approaching exhaustion of a deposit might in some cases be predicted. With regard to the origin of the gold in the Witwatersrand sediments, it is pointed out that the modified placer hypothesis is not fully equipped to explain certain of the variations in the composition of the gold.
- Full Text:
Pineapples in the Eastern Cape : a study of the farm economy and marketing patterns
- Authors: Strauss, Conrad B
- Date: 1961
- Subjects: Pineapple industry -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa , Farm produce -- Marketing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1103 , http://hdl.handle.net/10962/d1013318
- Description: The major objective of this study was to seek a better knowledge and greater understanding of the factors associated with successful pineapple farming in the Eastern Cape Region of the Union of South Africa. As no previous · investigation equally representative of commercial pineapple farming patterns in the Eastern Cape has been made, this study can be regarded as a pilot survey of the labour structures, rates of production, combination of enterprises; marketing channels and the suitability of various districts in the region of study for the production of pineapples. In addition, the history of the pineapple in South Africa will be traced briefly, and the position the Union holds as a supplier of pineapples on the world market, will be investigated. the importance of the Eastern Cape as a producer of pineapples in South Africa is well known, but is also unequivocally illustrated by the information in Table 1. According to estimates made by the Division of Economics and Markets for 1955/56 season, no less than 86.5 percent of the total acreage planted to pineapples in South Africa, was located in this area. Bathurst, East London and Albany, three of the six districts included in the estimate, were particularly prominent. Taken together, they cultivated more than three-quarters of the total area planted to pineapples in the Eastern Cape, and nearly 70 per cent of the total for South Africa. The remaining quarter of the area cultivated in the Eastern Cape was located in the districts of Peddie, Komgha and Alexandria.
- Full Text:
- Authors: Strauss, Conrad B
- Date: 1961
- Subjects: Pineapple industry -- South Africa -- Eastern Cape , Agriculture -- Economic aspects -- South Africa , Farm produce -- Marketing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1103 , http://hdl.handle.net/10962/d1013318
- Description: The major objective of this study was to seek a better knowledge and greater understanding of the factors associated with successful pineapple farming in the Eastern Cape Region of the Union of South Africa. As no previous · investigation equally representative of commercial pineapple farming patterns in the Eastern Cape has been made, this study can be regarded as a pilot survey of the labour structures, rates of production, combination of enterprises; marketing channels and the suitability of various districts in the region of study for the production of pineapples. In addition, the history of the pineapple in South Africa will be traced briefly, and the position the Union holds as a supplier of pineapples on the world market, will be investigated. the importance of the Eastern Cape as a producer of pineapples in South Africa is well known, but is also unequivocally illustrated by the information in Table 1. According to estimates made by the Division of Economics and Markets for 1955/56 season, no less than 86.5 percent of the total acreage planted to pineapples in South Africa, was located in this area. Bathurst, East London and Albany, three of the six districts included in the estimate, were particularly prominent. Taken together, they cultivated more than three-quarters of the total area planted to pineapples in the Eastern Cape, and nearly 70 per cent of the total for South Africa. The remaining quarter of the area cultivated in the Eastern Cape was located in the districts of Peddie, Komgha and Alexandria.
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The border region : a geographical study of land utilization
- Authors: Board, Christopher
- Date: 1961
- Subjects: Land use -- South Africa -- Cape of Good Hope , Vegetation and climate -- South Africa -- Cape of Good Hope , Geology -- South Africa -- Cape of Good Hope , Cape of Good Hope (South Africa) -- Environmental conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4884 , http://hdl.handle.net/10962/d1013512
- Description: From Summary: This is a geographical study of land use in the Eastern Cape Province. The land use pattern, although related closely to the features of the natural environment, is perhaps even more closely related to the spatial variations of the man-made environment, particularly to the disposition of the different racial groups with their different cultures and economies, and to the kaleidoscopic character of the settlement pattern.
- Full Text:
- Authors: Board, Christopher
- Date: 1961
- Subjects: Land use -- South Africa -- Cape of Good Hope , Vegetation and climate -- South Africa -- Cape of Good Hope , Geology -- South Africa -- Cape of Good Hope , Cape of Good Hope (South Africa) -- Environmental conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4884 , http://hdl.handle.net/10962/d1013512
- Description: From Summary: This is a geographical study of land use in the Eastern Cape Province. The land use pattern, although related closely to the features of the natural environment, is perhaps even more closely related to the spatial variations of the man-made environment, particularly to the disposition of the different racial groups with their different cultures and economies, and to the kaleidoscopic character of the settlement pattern.
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The geology of the Miami Mica field (Urungwe District)
- Authors: Wiles, J W
- Date: 1961
- Subjects: Geology -- Zimbabwe -- Urungwe District , Mines and mineral resources -- Zimbabwe -- Urungwe District , Mica -- Zimbabwe -- Urungwe District
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5071 , http://hdl.handle.net/10962/d1013503
- Description: [Preface] The detailed geological survey of the country described in this bulletin commenced in 1953 and was completed in 1956 with the mapping of 1,480 square miles of country. Information is supplied on 227 mines which produced mica alone or both mica and beryl, and 134 mines which produced only beryl. In addition, wolfram, gold, graphite, kyanite and rutile deposits and mines are described. Mineral outputs are given up to end of 1959. The field mapping and writing of the bulletin is entirely the work of Mr. Wiles. Mapping of the Field has established that, with a few exceptions, a metamorphic control has operated in the development of economic sheet mica and has led to the conclusion that very many of these pegmatites are composite bodies which have derived their material from two sources: one metamorphic and the other igneous. This conclusion was arrived at after a detailed petrographic investigation of the metamorphic rocks. The map at the end of this bulletin was drawn by Mr.A. H. Barrie and the diagrams are largely the work of Mr. D. O. L. Levy. Chemical analyses are by Messrs. A. J. Radford and E. Golding and were made in the Geological Survey Laboratory. Some of the photographs are by H. J. Cotterel of the Geological Survey while the remainder were taken by the Planning and Technical Services of the Federal Ministry of Home Affairs (formerly the Federal Information Department). It gives me pleasure to acknowledge the assistance and facilities offered the Department by mining men and residents in the district.
- Full Text:
- Authors: Wiles, J W
- Date: 1961
- Subjects: Geology -- Zimbabwe -- Urungwe District , Mines and mineral resources -- Zimbabwe -- Urungwe District , Mica -- Zimbabwe -- Urungwe District
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5071 , http://hdl.handle.net/10962/d1013503
- Description: [Preface] The detailed geological survey of the country described in this bulletin commenced in 1953 and was completed in 1956 with the mapping of 1,480 square miles of country. Information is supplied on 227 mines which produced mica alone or both mica and beryl, and 134 mines which produced only beryl. In addition, wolfram, gold, graphite, kyanite and rutile deposits and mines are described. Mineral outputs are given up to end of 1959. The field mapping and writing of the bulletin is entirely the work of Mr. Wiles. Mapping of the Field has established that, with a few exceptions, a metamorphic control has operated in the development of economic sheet mica and has led to the conclusion that very many of these pegmatites are composite bodies which have derived their material from two sources: one metamorphic and the other igneous. This conclusion was arrived at after a detailed petrographic investigation of the metamorphic rocks. The map at the end of this bulletin was drawn by Mr.A. H. Barrie and the diagrams are largely the work of Mr. D. O. L. Levy. Chemical analyses are by Messrs. A. J. Radford and E. Golding and were made in the Geological Survey Laboratory. Some of the photographs are by H. J. Cotterel of the Geological Survey while the remainder were taken by the Planning and Technical Services of the Federal Ministry of Home Affairs (formerly the Federal Information Department). It gives me pleasure to acknowledge the assistance and facilities offered the Department by mining men and residents in the district.
- Full Text:
The spectrochemical determination of certain minor trace elements in plant material
- Authors: Eve, Desmond John
- Date: 1961
- Subjects: Trace elements Spectrum analysis Plants -- Analysis Plants -- Effect of trace elements on Trace elements in agriculture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4469 , http://hdl.handle.net/10962/d1011773
- Description: A study has been made of three organic complexing reagents , namely dithizone, oxine and cupferron with a view to developing suitable methods for the separation and concentration of Zn, Co, Ni, Pb, Cu, Mn, Ti , V and Mo prior to the spectrometric determination of their concentrations. In particular the influence of pH on the chloroform extraction of ditihizonates, oxinates and cupferrates from aqueous tartrate and citrate solutions and the separation of iron by oxine extraction has been investigated. The development of a method for the chemical concentration and spectrcgraphic determination of Zn, Co, Ni, Pb, Ti, V and Mo is described and the possibility of determining Nn and Cu flame photometrically as part of the analysis scheme is demonstrated. A specially designed slide rule for the calculation of spectrographic results is described. A direct reading spectrometric method for the determination of Zn, Pb and Cu in plant material is presented. The analysis of plant ash for zinc using the 2138 . 6A spectrum line has been studied and a simple, rapid analysis method is described.
- Full Text:
- Authors: Eve, Desmond John
- Date: 1961
- Subjects: Trace elements Spectrum analysis Plants -- Analysis Plants -- Effect of trace elements on Trace elements in agriculture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4469 , http://hdl.handle.net/10962/d1011773
- Description: A study has been made of three organic complexing reagents , namely dithizone, oxine and cupferron with a view to developing suitable methods for the separation and concentration of Zn, Co, Ni, Pb, Cu, Mn, Ti , V and Mo prior to the spectrometric determination of their concentrations. In particular the influence of pH on the chloroform extraction of ditihizonates, oxinates and cupferrates from aqueous tartrate and citrate solutions and the separation of iron by oxine extraction has been investigated. The development of a method for the chemical concentration and spectrcgraphic determination of Zn, Co, Ni, Pb, Ti, V and Mo is described and the possibility of determining Nn and Cu flame photometrically as part of the analysis scheme is demonstrated. A specially designed slide rule for the calculation of spectrographic results is described. A direct reading spectrometric method for the determination of Zn, Pb and Cu in plant material is presented. The analysis of plant ash for zinc using the 2138 . 6A spectrum line has been studied and a simple, rapid analysis method is described.
- Full Text:
Insecticide resistance in the blue tick, Boophilus Decoloratus Koch, in South Africa
- Authors: Whitehead, G B
- Date: 1960
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5897 , http://hdl.handle.net/10962/d1013426
- Description: The work described in this dissertation was undertaken in an attempt to obtain a better understanding of the causes and relationships of insecticide resistance in Blue Tick, Boophilus decoloratus Koch, which has become an acute problem in some localities of the country. The work was undertaken at the Research Department of African Explosives and Chemical Industries Limited over a period of six years from 1953 to 1958. An attempt has been made to keep up to date with the published literature on the various aspects of these investigations up until the end of 1958. Information gained from the literature subsequent to end of 1958 has been made use of but it has not been possible for a number of reasons to follow all recent developments in the various aspects of insecticide resistance published during 1959. In the execution of this work assistance has been obtained from colleagues better equipped in the field of organic chemistry, biochemistry and statistics, than the author. Where information so gained has been used it has been duly acknowledged. Considerable assistance was rendered by laboratory assistants who were responsible for performing the considerable amount of routine collection, breeding and testing of the biological material. The blue tick is not a convenient experimental organism for studies on insecticide resistance. Even with the best facilities the tick cannot be bred satisfactorily and in consequence all supplies had to be collected from naturally-occurring populations. Although this had decided advantages in some aspects of the work, a great deal of useful information might have been obtained if certain strains of ticks could have been maintained. The lack of a standard sensitive reference strain has been a considerable disadvantage which could not be overcome and which has influenced the manner in which this work has been carried out. Because the tick could not be bred artificially the work could only be undertaken with unfed larvae and fully engorged adult females . Larvae are extremely small and in consequence could only be handled in batches while the fully engorged female is sluggish and contains a large quantity of semi-digested mammalian blood which invariably interfered with chemical or biochemical studies.
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- Authors: Whitehead, G B
- Date: 1960
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5897 , http://hdl.handle.net/10962/d1013426
- Description: The work described in this dissertation was undertaken in an attempt to obtain a better understanding of the causes and relationships of insecticide resistance in Blue Tick, Boophilus decoloratus Koch, which has become an acute problem in some localities of the country. The work was undertaken at the Research Department of African Explosives and Chemical Industries Limited over a period of six years from 1953 to 1958. An attempt has been made to keep up to date with the published literature on the various aspects of these investigations up until the end of 1958. Information gained from the literature subsequent to end of 1958 has been made use of but it has not been possible for a number of reasons to follow all recent developments in the various aspects of insecticide resistance published during 1959. In the execution of this work assistance has been obtained from colleagues better equipped in the field of organic chemistry, biochemistry and statistics, than the author. Where information so gained has been used it has been duly acknowledged. Considerable assistance was rendered by laboratory assistants who were responsible for performing the considerable amount of routine collection, breeding and testing of the biological material. The blue tick is not a convenient experimental organism for studies on insecticide resistance. Even with the best facilities the tick cannot be bred satisfactorily and in consequence all supplies had to be collected from naturally-occurring populations. Although this had decided advantages in some aspects of the work, a great deal of useful information might have been obtained if certain strains of ticks could have been maintained. The lack of a standard sensitive reference strain has been a considerable disadvantage which could not be overcome and which has influenced the manner in which this work has been carried out. Because the tick could not be bred artificially the work could only be undertaken with unfed larvae and fully engorged adult females . Larvae are extremely small and in consequence could only be handled in batches while the fully engorged female is sluggish and contains a large quantity of semi-digested mammalian blood which invariably interfered with chemical or biochemical studies.
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The frontier in South African English verse : 1820-1927
- Authors: Taylor, Avis Elizabeth
- Date: 1960
- Subjects: South African poetry (English) -- 19th century , South African literature (English) -- History and criticism , South Africa -- In literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2318 , http://hdl.handle.net/10962/d1013347
- Description: The concept of a distinctively South African poetry in English has been, and still is, derided as a "pipe dream" as part of the fallacy which stems from the desire for a "national" literature. In 1955, for instance, C.J. Harvey (in an article containing much common sense as well as sound literary judgment) denounced the self-conscious hunting for "Local Colour" which engrosses so many South African writers. Harvey claimed: "Our civilization is not "South African", except in trivial details, it is Western European, and more specifically as far as poetry written in English is concerned, English ... ". There is a serious error of emphasis here. It would be more accurate to say that our ancestors brought Western European civilization to this continent. To imagine that this civilisation has not undergone and is not still constantly suffering a subtle but far-reaching metamorphosis in Africa would be to fly in the face of reality. White South Africans do not only carry the same identity-card but they can be distinguished from Frenchmen, Englishmen or Irishmen by more than "trivial details". This thesis is an examination of some af the earliest English written in southern Africa, particularly of the verse produced by our poetasters and near-poets. It attempts, during the course of this examination, to call attention to a few of the more significant changes which have arisen as the result of the importation of Western civilsation to an African frontier. Further I hope to show some at the varying ways in which these differences affected the white pioneer and how this has been reflected in our verse since pioneering times. In this sense the Frontier may be thought of as the background against which South African English writers developed certain characteristic traits. Intro., p. 1-2.
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- Authors: Taylor, Avis Elizabeth
- Date: 1960
- Subjects: South African poetry (English) -- 19th century , South African literature (English) -- History and criticism , South Africa -- In literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2318 , http://hdl.handle.net/10962/d1013347
- Description: The concept of a distinctively South African poetry in English has been, and still is, derided as a "pipe dream" as part of the fallacy which stems from the desire for a "national" literature. In 1955, for instance, C.J. Harvey (in an article containing much common sense as well as sound literary judgment) denounced the self-conscious hunting for "Local Colour" which engrosses so many South African writers. Harvey claimed: "Our civilization is not "South African", except in trivial details, it is Western European, and more specifically as far as poetry written in English is concerned, English ... ". There is a serious error of emphasis here. It would be more accurate to say that our ancestors brought Western European civilization to this continent. To imagine that this civilisation has not undergone and is not still constantly suffering a subtle but far-reaching metamorphosis in Africa would be to fly in the face of reality. White South Africans do not only carry the same identity-card but they can be distinguished from Frenchmen, Englishmen or Irishmen by more than "trivial details". This thesis is an examination of some af the earliest English written in southern Africa, particularly of the verse produced by our poetasters and near-poets. It attempts, during the course of this examination, to call attention to a few of the more significant changes which have arisen as the result of the importation of Western civilsation to an African frontier. Further I hope to show some at the varying ways in which these differences affected the white pioneer and how this has been reflected in our verse since pioneering times. In this sense the Frontier may be thought of as the background against which South African English writers developed certain characteristic traits. Intro., p. 1-2.
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The junior secondary course of the Cape Province and the dull-normal child : (a pilot study based on research in the Border area and the North-Eastern districts)
- Authors: Loots, Francois Jacobus
- Date: 1960
- Subjects: Education, Secondary -- South Africa -- Cape of Good Hope , Children -- Intelligence levels , Children with mental disabilities -- Education -- South Africa -- Cape of Good Hope
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1994 , http://hdl.handle.net/10962/d1013501
- Description: [Aims of Dissertation and Investigation, p. ix-x] The aim of this dissertation is to analyse and evaluate the results of the new junior secondary course in respect of the dull-normal child ... How well did the junior secondary course succeed in meeting the needs of the dull-normal child? That is the question which this investigation will attempt to answer.
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- Authors: Loots, Francois Jacobus
- Date: 1960
- Subjects: Education, Secondary -- South Africa -- Cape of Good Hope , Children -- Intelligence levels , Children with mental disabilities -- Education -- South Africa -- Cape of Good Hope
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1994 , http://hdl.handle.net/10962/d1013501
- Description: [Aims of Dissertation and Investigation, p. ix-x] The aim of this dissertation is to analyse and evaluate the results of the new junior secondary course in respect of the dull-normal child ... How well did the junior secondary course succeed in meeting the needs of the dull-normal child? That is the question which this investigation will attempt to answer.
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Ionospheric studies of the solar eclipse 25 December, 1954
- Authors: McElhinny, M W
- Date: 1959
- Subjects: Ionosphere -- Research , Solar eclipses
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5531 , http://hdl.handle.net/10962/d1012869
- Description: Since the Kennelly- Heaviside hypothesis in 1902 of the existence of a partially conducting layer in the upper atmosphere was proved to be true by the experiments of APPLETON and BARNETT (1925) and BREIT and TUVE (1926), this region has become known as the ionosphere. The ionosphere was soon discovered to consist of, not one but several layers (Fig. 1) (i) A layer at a height of just over 100 km. called the E layer. (ii) A layer at a height of approximately 300km. called the F₂ layer. (iii) A layer at a height of approximately 200 km. called the F₁ layer; this layer differs from the other two in that it is only present during the day time in Summer. (iv) Occasional intense reflections from a height of about 100 km. are found - these cannot be attributed to the normal E layer and have received the name "Sporadic E". The presence of two E layers (E₁ and E₂) has been suggested by HALLIDAY (1936) and BEST and RATCLIFFE (l978) but until recently most workers still seem to attribute these reflections to Sporadic E. Recent measurement by rockets of the electron density at E layer heights still do not confirm whether such bifurcation exists in the E region. The diurnal and seasonal variations of the first three layers indicate that the sun is the chief agent in their production. It is generally agreed that these layers consist of ionised molecules or atoms and free electrons produced by radiation from the sun. The origin of Sporadic E ionisation is still obscure, but it is thought that these sudden increases in ionisation which occur in E layer heights are due to passing meteors. Recently it has also been suggested by SEDDON, PICKAR and JACKSON (1954) from rocket measurements that Sporadic E might be due to a steep electron density gradient above the B layer.
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- Authors: McElhinny, M W
- Date: 1959
- Subjects: Ionosphere -- Research , Solar eclipses
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5531 , http://hdl.handle.net/10962/d1012869
- Description: Since the Kennelly- Heaviside hypothesis in 1902 of the existence of a partially conducting layer in the upper atmosphere was proved to be true by the experiments of APPLETON and BARNETT (1925) and BREIT and TUVE (1926), this region has become known as the ionosphere. The ionosphere was soon discovered to consist of, not one but several layers (Fig. 1) (i) A layer at a height of just over 100 km. called the E layer. (ii) A layer at a height of approximately 300km. called the F₂ layer. (iii) A layer at a height of approximately 200 km. called the F₁ layer; this layer differs from the other two in that it is only present during the day time in Summer. (iv) Occasional intense reflections from a height of about 100 km. are found - these cannot be attributed to the normal E layer and have received the name "Sporadic E". The presence of two E layers (E₁ and E₂) has been suggested by HALLIDAY (1936) and BEST and RATCLIFFE (l978) but until recently most workers still seem to attribute these reflections to Sporadic E. Recent measurement by rockets of the electron density at E layer heights still do not confirm whether such bifurcation exists in the E region. The diurnal and seasonal variations of the first three layers indicate that the sun is the chief agent in their production. It is generally agreed that these layers consist of ionised molecules or atoms and free electrons produced by radiation from the sun. The origin of Sporadic E ionisation is still obscure, but it is thought that these sudden increases in ionisation which occur in E layer heights are due to passing meteors. Recently it has also been suggested by SEDDON, PICKAR and JACKSON (1954) from rocket measurements that Sporadic E might be due to a steep electron density gradient above the B layer.
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Linkage in extra-sensory perception
- Authors: Marsh, Maurice Clement
- Date: 1959
- Subjects: Telepathy , Extrasensory perception
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3215 , http://hdl.handle.net/10962/d1012840
- Description: The aims of this investigation were firstly to find whether 371 subjects, mainly students at Rhodes University, would be able to reproduce target drawings made 470 miles away by an agent in Cape Town, by means of General Extra-Sensory Perception; secondly, to find whether any association existed between any such hit scoring ability shown and personality ratings derived from a battery of personality test material; and thirdly, to find whether providing the subjects with material designed to link them more closely with the agent would increase their scoring rate. The 17,440 drawings returned by the subjects were randomised, and scored against a randomised set of 100 drawings consisting of 50 which had actually been used as targets, intermixed with 50 that were equal in difficulty but which had not been used as targets, and which were inserted merely as controls. Three independent judges assessed the subjects' drawings, and awarded hits in terms of title, shape and association. In the crucial title hits highly significant deviations in favour of the experimental target drawings were found, the control series of drawings showing no such effects. It was found that the subjects' hits were distributed evenly throughout the whole 25 day period of the experiment for each target, and showed no tendency to occur more frequently in the week a particular drawing was being used as a target than in the other weeks when it was not. When the subjects were divided into a high scoring and low-scoring group in terms of their E.S. P. abiility, the high- scoring group proved to be significantly more extraverted (as measured by the Bernreuter B3I scale) than the low- scoring group, confirming a relationship previously reported by Humphrey. In addition the data showed several other relationships, predicted by the work of previous experimenters, although these did not reach the .01 level of statistical significance. To assess the effect of the Linkage Material the subjects were divided into an experimental and a control group. The Experimental Group was supplied with correct Linkage Material, the Control Group with incorrect Linkage Material, which they were led to believe was correct . The two sets of Linkage Material were equated in all other respects. The Experimental Group showed significant improvements in scoring rate when supplied with a photograph and description of the agent, and a probably significant improvement when supplied with squares of handkerchief which had previously belonged to him. When supplied with squares of colour, also appearing on the agent's target sheets, no significant increase in scoring rate took place on the target drawings, but a significant decrease occurred in hits scored on the control targets. By contrast no consistent significant fluctuations were shown by Control Group Subjects, leading to the conclusion that the correctness of the Linkage Material was a factor contributing to its effectiveness. A qualitative examination of the hits scored by the subjects revealed that they tended to reproduce the concepts depicted by the target drawings, rather than the actual shapes drawn by the agent, suggesting that the hits were being produced by a telepathic process rather than a clairvoyant one. The results of the experiment suggest that the subjects were assisted by the Linkage Material to gain access to the agent's mind as a whole, and not to particular items in it. This throws doubt on the correctness of Whately Carington's Association Theory of Telepathy, which the experiment was designed to test.
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- Authors: Marsh, Maurice Clement
- Date: 1959
- Subjects: Telepathy , Extrasensory perception
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3215 , http://hdl.handle.net/10962/d1012840
- Description: The aims of this investigation were firstly to find whether 371 subjects, mainly students at Rhodes University, would be able to reproduce target drawings made 470 miles away by an agent in Cape Town, by means of General Extra-Sensory Perception; secondly, to find whether any association existed between any such hit scoring ability shown and personality ratings derived from a battery of personality test material; and thirdly, to find whether providing the subjects with material designed to link them more closely with the agent would increase their scoring rate. The 17,440 drawings returned by the subjects were randomised, and scored against a randomised set of 100 drawings consisting of 50 which had actually been used as targets, intermixed with 50 that were equal in difficulty but which had not been used as targets, and which were inserted merely as controls. Three independent judges assessed the subjects' drawings, and awarded hits in terms of title, shape and association. In the crucial title hits highly significant deviations in favour of the experimental target drawings were found, the control series of drawings showing no such effects. It was found that the subjects' hits were distributed evenly throughout the whole 25 day period of the experiment for each target, and showed no tendency to occur more frequently in the week a particular drawing was being used as a target than in the other weeks when it was not. When the subjects were divided into a high scoring and low-scoring group in terms of their E.S. P. abiility, the high- scoring group proved to be significantly more extraverted (as measured by the Bernreuter B3I scale) than the low- scoring group, confirming a relationship previously reported by Humphrey. In addition the data showed several other relationships, predicted by the work of previous experimenters, although these did not reach the .01 level of statistical significance. To assess the effect of the Linkage Material the subjects were divided into an experimental and a control group. The Experimental Group was supplied with correct Linkage Material, the Control Group with incorrect Linkage Material, which they were led to believe was correct . The two sets of Linkage Material were equated in all other respects. The Experimental Group showed significant improvements in scoring rate when supplied with a photograph and description of the agent, and a probably significant improvement when supplied with squares of handkerchief which had previously belonged to him. When supplied with squares of colour, also appearing on the agent's target sheets, no significant increase in scoring rate took place on the target drawings, but a significant decrease occurred in hits scored on the control targets. By contrast no consistent significant fluctuations were shown by Control Group Subjects, leading to the conclusion that the correctness of the Linkage Material was a factor contributing to its effectiveness. A qualitative examination of the hits scored by the subjects revealed that they tended to reproduce the concepts depicted by the target drawings, rather than the actual shapes drawn by the agent, suggesting that the hits were being produced by a telepathic process rather than a clairvoyant one. The results of the experiment suggest that the subjects were assisted by the Linkage Material to gain access to the agent's mind as a whole, and not to particular items in it. This throws doubt on the correctness of Whately Carington's Association Theory of Telepathy, which the experiment was designed to test.
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