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The solubility of mercurous chloride in water at 25°C

- Clur, Dennis Alwin

  • Authors: Clur, Dennis Alwin
  • Date: 1959
  • Subjects: Mercury compounds -- Solubility , Mercuric chloride
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4522 , http://hdl.handle.net/10962/d1014705
  • Description: [From Introduction]. In 1955, Dry and Gledhill, both formerly of this Department, published their paper on the Solubility of Mercurous Chloride in Water at 25°0, and it was originally intended that this thesis should be an extension of the study to cover the temperature range from 5 t o 55°0. A preliminary investigation at 25°0, however, failed to yield results which were consistent with their findings, even though their apparatus and experimental technique were used. In an effort to resolve these difficulties their method of saturating the calomel in the conductance cell was thoroughly investigated, and as this procedure was found to be responsible, it was necessary to evolve an entirely new approach. The technique finally adopted was to saturate the mercurous chloride solutions by mechanical stirring in siliconed vessels and to carry out the conductance, pH, and total mercury concentration measurements on the filter ed solution. This method gave good results, and was free from the many extrapolations prevalent in the original procedure.
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  • Date Issued: 1959

The sorption of Hydrochloric Acid and Potassium Hydroxide by mohair and wool

- Bamford, Graeme Reginald Ernest

  • Authors: Bamford, Graeme Reginald Ernest
  • Date: 1959
  • Subjects: Hydrochloric acid -- Absorption and adsorption , Hydroxides -- Absorption and adsorption , Wool , Mohair
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4452 , http://hdl.handle.net/10962/d1009503
  • Description: The main object of the present investigation has been to establish a titration curve for mohair keratin and to compare it with similar data for wool, to determine whether the differences in physical and chemical properties could be attributed in any way to the acidic and basic character of these fibres. As shown in subsequent discussion such measurements provide extremely useful information regarding the chemical structure of proteins in general, and in the technical fields involving processes such as wool scouring, carbonizing and dyeing. The study has been extended to include certain modified wools, i.e. photochemically damaged, and oxidized keratin. The most successful contribution to the titration data of wool keratin is the work of Steinhardt and Harris and subsequent authors have tended to adopt their procedures without modification. In the present study attempts have been made to obtain a clearer understanding of the fundamental processes. New techniques and analytical methods have been introduced to improve the accuracy of the measurements.
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  • Date Issued: 1959

The thermal decomposition of irradiated silver permanganate

- Sole, Michael John

  • Authors: Sole, Michael John
  • Date: 1959
  • Subjects: Decomposition (Chemistry) , Irradiation , Permanganates , Silver compounds , Metals -- Thermal properties
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4502 , http://hdl.handle.net/10962/d1013265
  • Description: The thermal decomposition of silver permanganate, pre-irradiated in BEPO and in a ⁶°C₀ Ϫ 'hot spot' has been investigated in the temperature range 100 - 125°C. The results are similar to those for irradiated KMn0₄ and the mechanism proposed for the latter is again suggested. The activation energy for the migration of point defects over the induction period is 1.03 ev. The decompositions of unirradiated and irradiated crystals differ in that the latter undergo physical disintegration over the acceleratory period. X-ray studies immediately prior to disintegration show strain and fragmentation in the irradiated crystal. An explanation involving the annealing of point defects at dislocation is advanced to explain the changes produced in the p/t plots with increased dosage, and fixed decomposition temperature. Summary, p. 94.
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  • Date Issued: 1959

A critical study of the curcumin method for the determination of boron in plant material

- Davidson, R J

  • Authors: Davidson, R J
  • Date: 1958
  • Subjects: Plants -- Nutrition , Boron , Turmeric
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4458 , http://hdl.handle.net/10962/d1011003
  • Description: Methods for the determination of boron are reviewed. A thorough investigation of the curcumin method was undertaken. Factors such as spectral absorption, boron volatilisation and the effects of pH, the stability of reagents and colour solutions, the drying of reaction products and the interference from certain elements, were investigated. A study of the efficiency of extracting boron from plant material using an ashing procedure is presented. The modified curcumin method for the determination of boron in plant material is described. The statistical accuracy and precision of the modified method is presented. The modified method was used to determine the boron content in citrus and pineapple leaf samples obtained from various parts of the Eastern Cape.
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  • Date Issued: 1958

An investigation of isolated bursts of solar radio noise

- Shuter, William Leslie Hazlewood

  • Authors: Shuter, William Leslie Hazlewood
  • Date: 1958
  • Subjects: Solar physics -- Research , Solar radio emission
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5539 , http://hdl.handle.net/10962/d1013216
  • Description: The literature on isolated bursts and possible mechanisms of origin has been critically reviewed, and observations point to a mechanism involving omission of electromagnetc radiation from plasma oscillations in the solar corona excited by outward travelling disturbances. Solar noise observations on 125 Mc./s. recorded at Rhodes University during the period November 26 1957 - February 6 1958 have been analysed by the author for isolated bursts, and these observations show the same general features reported by previous investigators. In interpretation of these records particular attention has been devoted to two aspects of isolated bursts; namely the preponderance on single frequency records of double-humped bursts, and the shape of isolated burst profiles. The authors suggests that a probable explanation of double-humped bursts observed on any frequency f is that the first hump represents omission at or near the level of zero refractive index for f radiation, and that the second hump corresponds to harmonic omission at the f/2 level. Source velocities may be calculated from the time delay between the peaks and an average value of 2 x 10⁴ km./sec. was obtained from an analysis of 21 double-humped bursts. This value is in very good agreement with that deduced by Wild (1950b) from the rate of frequency drift of peak intensity of isolated bursts. Simple isolated bursts had decay profiles which are approximatley exponential in shape, and this is usually interpreted in terms of the natural decay of plasma oscillations in the medium of origin. The author has verified that the exponential function is a good fit to the observed decay profiles, but shows that a relation of the form I - ¹/n (superscript) ⋉ t (where I is intensity and t is time) fits just as well. An alternative model is suggested which would lead to an exponential-like decay profile which is not determined by the natural decay of plasma oscillations. The work concludes with some suggestions for further research.
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  • Date Issued: 1958

Correlation of the feeding habits, jaw musculature and type of teeth of some South African golden moles

- Thelejane, Thomas Sohl

  • Authors: Thelejane, Thomas Sohl
  • Date: 1958
  • Subjects: Moles (Animals) -- Food , Insectivores (Mammals)
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5892 , http://hdl.handle.net/10962/d1013385
  • Description: The jaw musculature and its innervation in the Chrysochloridae studied is typicaly mammalian except that the m. temporalis occupies the whole of the orbito-temporal fossa. The antemolar teeth are specialized, while the molars are simple and primitive. Normally the diet of Golden Moles consists of earthworms, insects in all stages of development and millipedes. The firm implantation of the antemolar teeth can be correlated with their function of catching the prey, while the molars are adapted for a worm-like diet. The available evidence indicates that the genera Bematiscus and Chrysospalax are more primitive than the other Golden Moles. Since Golden Moles feed on insects in all stares of development and millipedes, they can be considered as being of economic importance.
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  • Date Issued: 1958

Freedom in the thought of John Locke and John Stuart Mill

- Omer-Cooper, John David

  • Authors: Omer-Cooper, John David
  • Date: 1958
  • Subjects: Locke, John, 1632-1704 , Mill, John Stuart, 1806-1873 , Liberty , Ethics , Free thought , Autonomy (Psychology)
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2746 , http://hdl.handle.net/10962/d1012989
  • Description: Recent history has abundantly justified J. S. Mlll's theory that the power of soclety over the indivldual is llkely to increase without limlt If lt was not prevented. One of the most obvlous phenomena of our times has been the rise of the so-called totalltarlan systems of government; states that treat the lndlvldual as a being wlth no other end but the servlce of the state and which are prepared to use the advanced technlques which modern scientific research has made available to them to mould the individual as the perfect tool of the system.
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  • Date Issued: 1958

Synthetic ion exchange resins, incorporating asymmetric groups, as resolving agents

- O'Sullivan, Diarmid John

  • Authors: O'Sullivan, Diarmid John
  • Date: 1958
  • Subjects: Ion exchange resins -- Synthesis
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4485 , http://hdl.handle.net/10962/d1012991
  • Description: The object of this research is to further investigate the possiblitiy of resolving racemic bases on an optically active cation exchange resin. Any success in this direction would help to explain the reason for Bunnett and Mark's failure, since the general assumption that selective adsorption of one enantimorph of a racemic compound on an active exchanger should occur has been verified by Grubhofer and Schleith. The work can be conveniently divided into two sections. a) The preparation of optically active cation exchange resins and, b) the use of these as resolving agents. P. 8
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  • Date Issued: 1958

The development of the secretaryship to the government at the Cape of Good Hope under John Montagu, 1843-1852

- Breitenbach, J J

  • Authors: Breitenbach, J J
  • Date: 1958
  • Subjects: Montagu, John, 1797-1853 , Montagu family , Cape of Good Hope (Colony) -- Parliament -- Legislative Council , Cape of Good Hope (South Africa) -- History , Cape of Good Hope (South Africa) -- Politics and government
  • Language: English
  • Type: Thesis , Masters , MA
  • Identifier: vital:2620 , http://hdl.handle.net/10962/d1014603
  • Description: The development of the Cape Colony during the 'forties and early 'fifties last century is, indeed, a fascinating study. And as one aspect of it, a critical study analysis of the public career of John Montagu, while he was Colonial Secretary at the Cape, is of particular interest. For, by tracing the influence of his office in relation to the changing political, social and economic structures of the colony, it is hoped some contribution will be made to the knowledge of the period. Thus, the present thesis is, in part, an examination of the duties and responsibilities of the Colonial Office; but more particularly, it is an examination of how Montagu, who virtually dominated the Cape scene for almost a decade interpreted these duties and responsibilities. By concentrating, then, on his role in the civil administration and political management of colonial affairs, other aspects are revealed. The authority of the Colonial Office, which had through the years become a sort of government 'archives', was developed to such an extent, that every memorandum issued by it seems to set the tone for government policy. More. The very fact that Montagu was, time and again, left in charge of civil affairs at the Cape, while it reveals the dominant native problem and the vital question of defence, accounts also for the patenalism in government. The most important primary sources for this study have been the British Parliamentary Papers on Cape Affairs, the Cape of Good Hope Blue Books, Government House Records and the relevant minutes of the Executive and Legislative Councils. The Annual Almanacs of the Cape proved to be invaluable; they contain a wealth of information on the institutions of government, central and local, as well as the most indispensable returns for all the many services at the Cape.
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  • Date Issued: 1958

Wages and employment of European women in industry in Durban, 1955/56

- Mesham, Noreen Ina

Liquid junction potentials at mixed electrolyte salt bridges

- Finkelstein, Noel Phillip

  • Authors: Finkelstein, Noel Phillip
  • Date: 1957
  • Subjects: Hydrogen-ion concentration -- Measurement , Hydrogen-ion concentration , Electrochemistry
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4473 , http://hdl.handle.net/10962/d1011835 , Hydrogen-ion concentration -- Measurement , Hydrogen-ion concentration , Electrochemistry
  • Description: The potentiometric method is one of the most exact techniques of electrochemistry. Its use is widespread in both routine measurements, such as pH determination, and in applications which demand the highest accuracy. Perhaps its severest limitation is the error due to liquid junction potentials. Although this has been the subject of much study, and although various means of combating it have been proposed, it has defied all attempts at a satisfactory solution. Indeed, so serious is the position that it has become the accepted practice in the more accurate fields to abandon altogether the use of potentiometric techniques in favour of others, usually less convenient and otherwise less accurate, when the presence of liquid junctions cannot be avoided. Intro. p. 1.
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  • Date Issued: 1957

Photofluorescence decay times of organic phosphors

- Hamilton, T D S

  • Authors: Hamilton, T D S
  • Date: 1957
  • Subjects: Fluorescence , Phosphorescence
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5525 , http://hdl.handle.net/10962/d1012136 , Fluorescence , Phosphorescence
  • Description: The absorption and emission of energy is a fundamental property of any atomic system.When the emission occurs in the visible or near visible region the phenomenon is usually referred to as luminescence or fluorescence. This must be distinguished from thermal radiation as it does not follow Kirchoff's law.
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  • Date Issued: 1957

Some aspects of the animal ecology of Rhenosterbos: Elytropappus rhinocerotis (L.f.) Less

- Shiff, Clive Julian

  • Authors: Shiff, Clive Julian
  • Date: 1957
  • Subjects: Animal ecology -- South Africa , Rhenosterbos
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5880 , http://hdl.handle.net/10962/d1013200
  • Description: Rhenosterbos, Elytropappus rhinocerotis (L.f.) Less belongs to a purely South African section ot the Compositae. It is restricted to an area of low rainfall which is evenly distributed over the year. The plant is a specialised xerophyte with minute leaves and white pubescent twiglets. Older stems become woody and dry and bear no leaves. The shrubs have a life span of about eight years; the plants are most succulent and luxurious during the third and fourth year, after which they tend to become woody and scraggly. For this investigation insect material was obtained by sweep-net collection and field observation. In the Grahamatown district 78 collections were made during the period March - November 1953, with data thus obtained being embodied in this work. In addition to this, collections were made in the Cradock-Hofmeyer, Uitenhage, Riversdale, Bot River, Swellendam and Stellenbosch districts. Twenty species of insects have been shown definitely to feed on the plant and there are another 13 which probably feed on it. Of the 20 species attached to the plant, 12 are sucking forms belonging to the Orders Homoptera and Hemipters. They include six Coccids, two Jassids a Cercopid, two Mirids and a Pentstomid. The Coleoptera are represented by one or perhaps two species which feed on the plant. The Lepidoptera are represented by two important species of moth, a Geometrid and a Pyralid. Four species of gall forming Diptera are associated with the plant. There are two species of Trypetidae which are responsible for piriform swellings of growth points and are distributed evenly throughout the bush. There are also two Cecidomyidae one of which develops in the growth points of the shoots and is responsible tor a minute tubular gall. The other develops in a fusiform stem gall. This latter gall has been shown to be more common on smaller bushes than on larger ones, implying that the adult female may show certain selective powers during oviposition. The size of the insect population is held in check by spiders mantids and other general predators. There are several Coccinellids which prey on the scale insects. Rhenosterbos supports a small, well regulated community of insects. The balance between plant and animal is very dellcate because of the high degree of specialisation of the plant. On occasions this balance has been known to break down, and the insects present in abundance have swamped and killed large patches of the plant.
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  • Date Issued: 1957

Studies on the biology of ants associated with citrus trees

- Myers, N J

  • Authors: Myers, N J
  • Date: 1957
  • Subjects: Citrus -- Diseases and pests -- Biological control -- South Africa , Ants -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5869 , http://hdl.handle.net/10962/d1012923
  • Description: Several ant species may be associated with the same honeydew producing insect in citrus orchards. Recently antagonism and competition between two such ants were reported from Letaba. This report stimulated the present study, the purpose of which is to ascertain which ant species are most numerous in citrus orchards ln the Eastern Cape Province; the reasons for these ants being able to occupy orchards; and, finally, their relationships. A survey of the Sundays River Valley and the Fish River Valley revealed that three species - Anoplolepis custodiens Smith, Anoplolepis steingroeveri Forel, and Pheidole megacephala Fabricius - were commonly found in citrus orchards in association with Soft Brown Scale insects. The territorial relationships of these ants were determined by plotting their distribution at intervals for over a year. It was found that this distribution could be correlated with seasonal climatic conditions, the effects of farming practices, brood rearing requirements and behavioural differences between the three species. The ant, A.steingroeveri, had not been previously studied, and since foraging is an integral part of territorial behaviour, some aspects of its biology, and more especially its foraging activity, were investigated to compare it with the known biology of the other two species. Observations on the foraging activity of A. steingroeveri were made at monthly lntervals for almost a year, and correlated with climatic conditions prevailing at the time. Some seasonal and dally variations in foraging behaviour could not be readily explained in terms of the effects of temperature and humidity on the ants. Other factors, includ1ng trophallactic stimulation and overcast skies, were found to influence ant activity. Owing to the apparent lack of information in the literature and possibility of periodic honeydew production by Soft Brown Scale insects controlling ant activity was investigated in the laboratory. The results of this study showed that it was not likely that honeydew excretion restricted the activity of the ants. Several investigators have also found that many interrelated climatic factors correlated with ant foraging behaviour, but have expressed dissatisfaction at not being able to reach the crux of the matter. To clarify the issue a constant temperature chamber was constructed in which a colony of Crematogaster ants was housed and the ants were subjected to a series of temperatures at different humidities, all other factors were eliminated or kept constant. The effects of these two factors on the thermokinetics and foraging activity of the ants were registered. This thesis contains several sections and at the end of each the results are discussed in the light of the available literature and comparisons are drawn between the species under investigation. The main results are given in the summary. After the summary two appendices are included. One is an attempt to compare the effect on ant size of the honeydew diet of orchard colonies with the proteinaceoue diet of veld ants. The other appendix is an experiment to control citrus ants with an insecticide.
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  • Date Issued: 1957

The morphology of the Weberian apparatus of Labeo umbratus Smith

- Dennis, Clive Roy

  • Authors: Dennis, Clive Roy
  • Date: 1957
  • Subjects: Fishes -- Anatomy -- South Africa , Weberian apparatus -- Morphology , Fishes -- South Africa -- Tyumie River , Eastern Cape (South Africa) -- Fishes
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5907 , http://hdl.handle.net/10962/d1014766
  • Description: In Labeo umbratus only the first three anterior vertebrae undergo any modification. These vertebrae are not completely anchylosed with each other and are closely associated with the four Weberian ossicles. Movement is however restricted between these vertebrae since this is essential for the efficient functioning of the Weberian ossicles. The first vertebra is well developed the absence of a spinous process and neural arch in the first vertebra may perhaps be explained by the findings of some workers who derive the claustrum from the former and the scaphium from the latter. A small muscle has its origin on the claustrum and its insertion in the angle formed by the dorsal and medial processes of the scaphium. A second muscle originates in the pit-like excavation of the first vertebra and is inserted on the ventral process of the scaphium. The intercalarium possesses horizontal, articular and ascending processes; a portion of the horizontal process being imbedded in the interossicular ligament. In Labeo umbratus it is unlikely that the intercalarium represents (if it does so at all) the entire neural arch of the second vertebra. From a morphological point of view it seems likely that the intercalarium may function as a lever. A transversely situated ductus endolymphaticus joins the two sacculi to each other. The sagitta, in the region of the ductus endolymphaticus has a long, lateral "wing-like" process which projects into the cavity of the sacculus. The sacculus anilagena are innervated by the n. saccularis and the n. lagenaris respectively. The ductus endolymphaticus is prolonged posteriorly into a median unpaired sinus endolymphaticus. Although the only serious objection to Weber's theory is the fact that there could be no differential action of the two ears, the basic idea seems valid. Sagemehl's theory cannot be accepted. It seems likely that the Weberian ossicles are necessary structures for audition and to the hydrostatia function of the air-bladder.
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  • Date Issued: 1957

The solubility of barium sulphate in water at 25°

- Rosseinsky, D R

  • Authors: Rosseinsky, D R
  • Date: 1957
  • Subjects: Chemistry, Physical and theoretical , Solubility , Barium sulfate
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:4491 , http://hdl.handle.net/10962/d1013097
  • Description: Barium sulphate is a widely used analytical precipitate and for this reason its properties have been extensively studied. The variety of results encountered with barium sulphate samples prepared by different methods is an indication of the complex nature of this interesting substance. Intro., p. 8.
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  • Date Issued: 1957

A preliminary study of adaptation and inhibition of reflex claw opening in the crab Potamon perlatus (Milne Edwards)

- Bush, Brian M H

  • Authors: Bush, Brian M H
  • Date: 1956
  • Subjects: Crabs , Decapoda
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5906 , http://hdl.handle.net/10962/d1014683
  • Description: The only recorded experimental attempt to determine the functional, biological significance of peripheral inhibition in the Crustacea is that of Hoffmann (1914). From a series of experiments on Astacus fluviatilis L. involving transsection of the opener inhibitor and motor axons of the cheliped, he concluded that the opener inhibitor axon of the claw responded to prolonged or repeated sensory stimulation by transmitting inhibitory impulses to the opener muscle, the peripheral inhibition thus evoked causing adaptation of the reflex opening responses of the claw to the sensory stimulation. This suggests that there may be (1) a very high degree of peripheral control of (a) the reactions of the animal to external stimuli, and perhaps also to proprioceptive stimuli, and therefore (b) of the behaviour of the animal; and (2) a correspondingly high degree of independence of this behaviour from central nervous control. It is therefore of importance to discover whether, in fact, this conclusion is valid for Astacus and other Decapod Crustacea, and if so, then to what extent the adaptation is peripherally controlled. A preliminary attempt haa been made to repeat these experiments of Hoffmann, using Potamon perlatus (M.Edw.). Experiments in which mechanical sensory stimulation was used to evoke reflex claw opening indicated that this conclusion is not applicable to P.perlatus. The adaptation of the mechanical claw openining responses which occurred with repeated sensory stimulation was not affected by transsection of either the specific opener inhibitor axon or the common inhibitor axon of the claw. It was evidently mainly due to sensory adaptation when the sensory stimuli were heavy, and to centrally controlled adaptation when the sensory stimuli were light. The significance of these results is discussed. Other effects observed during the course of the work, of electrical "sensory" stimulation, and of cerebral ganglion elimination, are also described and discussed in relation to the present problem.
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  • Date Issued: 1956

Robert Godlonton as architect of frontier opinion, with special reference to the politics of separatism, 1850-57

- Le Cordeur, Basil Alexander

Scientific management as applied to a South African sweet factory

- Bernstein, Jack

  • Authors: Bernstein, Jack
  • Date: 1956
  • Subjects: Candy industry -- Management , Candy industry -- South Africa
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:1111 , http://hdl.handle.net/10962/d1013494
  • Description: From Chapter 1: Among the many problems that the sweet industry in this country has had to overcome was the prejudice which favoured imported confectionery as against the local product. Fortunately this prejudice is slowly disappearing, firstly because imported sweets are largely unobtainable, and, secondly because the quality of the South African manufactured article has improved tremendously. Both the quantity and value of sweets produced in this country have increased over the last decade...
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  • Date Issued: 1956

Some aspects of the micro-arthropod fauna in the soils of pineapple fields in the Bathurst division, Eastern Cape Province

- Graham, P

  • Authors: Graham, P
  • Date: 1956
  • Subjects: Pineapple , Soils -- South Africa -- Eastern Cape , Soil surveys -- South Africa -- Eastern Cape , Soil science , Arthropoda -- South Africa , Arthropod pests -- South Africa , Soil animals
  • Language: English
  • Type: Thesis , Masters , MSc
  • Identifier: vital:5853 , http://hdl.handle.net/10962/d1012087 , Pineapple , Soils -- South Africa -- Eastern Cape , Soil surveys -- South Africa -- Eastern Cape , Soil science , Arthropoda -- South Africa , Arthropod pests -- South Africa , Soil animals
  • Description: Although a considerable amount of work has been done on the fauna of the soil of temperate forests and pastures, very little is known about that of tropical and sub-tropical soils. Most of the work on tropical soils concerns the fauna of tropical forests ... . The present investigation represents an attempt to discover the effect of an imported perennial tropical and sub-tropical plant, the Pineapple, on the soil fauna of a semi-arid region (rainfall 15-25 inches). Intro., p. 1-2
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  • Date Issued: 1956
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