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A preliminary investigation of the structure of green wattle tannin (acacia decurrens willd)

- Glueck, Leonard David

Authors: Glueck, Leonard David
Date: 1952
Subjects: Tannins , Tannin plants
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:4475 , http://hdl.handle.net/10962/d1011988 , Tannins , Tannin plants
Description: Green wattle tannin extracts were separated by lead salt precipitation into a phenolic tannin fraction and a nontannin fraction. The combustion analysis of the tannin fraction corresponded to an empirical formula C₁₅H₁₄O₆. Methoxy and acetyl values showed four oxygens were hydroxy groups while the residual oxygens could either be ether linked or carbonyl groups. Diazomethane methylation produced a white product of high methoxyl value which indicated that the four hydroxyl groups were phenolic. Chromatography of the lead salt purified tannin showed an indistinct non-fluorescent trail. Ether extraction of the tannin removed the associated Phenolic bodies. The ethereal extract unlike black wattle extracts contained no fisetin and evaporation of the ethereal solutions yielded a gummy non-crystalline residue. Alkaline fusion of the purified tannin produced for the first tlme a variety of acidic and phenolic compounds i.e. resorcinol, pyrogaloll, phloroglucinol β-resorcylic acid, gallic acid and protocatechuic acid. From the high yields of resorcinol (6%) and gallic acid (3%), these units appear to predominate. These degradation productions, coupled with the analytical figures, indicate a possible C₁₅ unit with resorcinol and pyrogallol nuclei as a basis. The non-tannin fraction failed to reveal any compound which might cause the excessive redness in green wattle extracts. Chromatography of this non-tannin fraction showed the presence of sucrose.
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A study of cation exchange in South African soils

- Du Toit, A A

Authors: Du Toit, A A
Date: 1952
Subjects: Soil chemistry , Ion exchange
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:4462 , http://hdl.handle.net/10962/d1011506 , Soil chemistry , Ion exchange
Description: The colloidal fraction is the vital part of a soil. These extremely minute particles determine the nature of the soil and are mainly responsible for its many and varied functions. The most important of these functions is perhaps the ability of the colloids to adsorb and exchange cations, the elements so essential to all organisms as building materials. When pure water is passed through a non-saline. soil, the leachate will contain very few dissolved cations. If, on the other hand, an electrolyte such as a weak solution of sodiun chloride, is passed through the same soil, the leachate will contain considerable quantities of calcium, magnesium and potassiun chlorides as well as much of the original sodium chloride. The number of equivalents of the cations collected will be approximately the same as the number of equivalents of sodium ions added. Sodium ions have displaced some of the calcian, magnesium and potassium ions from the soil. This phenomenon is known as cation exchange. Intro., p. 1.
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An historical survey of the Bethelsdorp station of the London Missionary Society, from its inception, and until the death of Doctor van der Kemp, in 1811

- Briggs, D Roy

Authors: Briggs, D Roy
Date: 1952
Subjects: London Missionary Society -- History , Bethelsdorp (South Africa) -- History
Language: English
Type: Thesis , Bachelor , BDiv
Identifier: vital:1290 , http://hdl.handle.net/10962/d1014609
Description: In South Africa the small town or hamlet, nestling - as is so often the case - at the foot of a mountain, frequently proclaims its identity to the traveller by inscribing its name in great, white-washed letters of stone upon the side of the hill. If this were the case with Bethelsdorp, the temptation would be to write on those bare, rocky hills, that form the back-drop for the drama a century and a half have seen on its stage, the one word, "Ichabod." For the glory has departed. And some would even question whether any of its days had been glorious. Around this small outpost of Christendom have centred, from its earliest beginnings, both praise and contumely. It is the purpose of this investigation to attempt to judge between these opinions, in an attempt to arrive at the truth, by a survey of the years Bethelsdorp enjoyed under the direction of Johannes Theodorus van der Kemp. He has had many critics, many protagonists: perhaps of no other man in the short history of this land has there been such diversity of opinion. Before the judgments of historians and biographers can be assessed, however, the facts of his work must be appreciated, and the effort towards understanding must be preceded by a brief description of the circumstances antecedent to the foundation of that station, which marked the summt of his life and work.
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Attempted synthesis of a [beta] or [gamma] resorcinyl alcohol

- Ryding, William Wallace

Authors: Ryding, William Wallace
Date: 1952
Subjects: Alcohol -- Synthesis , Resorcinol
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:4517 , http://hdl.handle.net/10962/d1014134
Description: The ultimate objective of this research is the elucidation of the mechanism of the resorcinol-formaldehyde condensation. Whilst a vast literature has been built up about the phenol- formaldehyde condensation, that of resorcinol has received but scant attention, probably because the high reactivity of resorcinol rendered the following of the condensation extremely difficult. The earliest observation concerning the resorcinol-formaldehyde condensation was due to Baeyer who, in 1872, condensed resorcinol with various aldehydes. When the aldehyde was relatively inactive crystalline compounds were obtalned but with acetaldehyde or formaldehyde a resinous product resulted. In 1892 Caro condensed an excess ot resorcinol with formaldehyde in the presence of dilute hydrochloric acid; the product obtained recrystallised from alcohol as white microsoopic crystals, decomposed without melting at 250° and was stated to be bis (2- 4 dihydroxyphenyl) methane ... In decidlng upon the most suitable lines of attack it would seem that a survey of the literature relating to the phenol-formaldehyde concentration which might be expected to be closely related to that of resorcinol, would be of value. Summary of p. 1-5
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German immigration to the Cape, with special reference to (a) the German military settlers of 1857; and (b) the German immigrants of 1858

- Schnell, E L G

Authors: Schnell, E L G
Date: 1952
Subjects: Germans -- South Africa -- Cape of Good Hope , Immigrants -- South Africa -- Cape of Good Hope , Cape of Good Hope (South Africa) -- History , Eastern Cape (South Africa) -- History
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:2613 , http://hdl.handle.net/10962/d1013168
Description: South Africa is a multi-racial society in more than one sense. There are the broad divisions of Colour, but in addition there are further divisions within each group. The European section is mostly of Dutch and British origin, but there are important other strains, notably the French and the German. The history of the Dutch and British sections has been written, and that of the French too, but the story of the German element is still incomplete. Preface.
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Investigation leading to a process for the synthesis of hydrogen sulphide from sulphur and certain lubricating oils derived from petroleum

- Schauder, H

Authors: Schauder, H
Date: 1952
Subjects: Hydrogen sulfide
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:4499 , http://hdl.handle.net/10962/d1013160
Description: The primary object of the present study was to provide a process adaptable to prevailing South African conditions, for the manufacture of hydrogen sulphide. Such a process would also be suitable for use in other countries where the gas is not obtainable naturally or from refinery operations or as a by-product from other industries. Early in the study it was found that the literature embodying prior work was very scattered in character and had to be sought in many different fields of research. It was therefore decided to make the record of prior work as comprehensive as possible so as to provide, at the same time, a starting point tor future workers on related subjects. Intro., p. 1.
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Some comparative studies of the fauna in soils developed under natural forest, pine and bluegum

- Watts, John Christopher David

Authors: Watts, John Christopher David
Date: 1952
Subjects: Soil science , Forest ecology , Soil animals
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5895 , http://hdl.handle.net/10962/d1013423
Description: [From Introduction] It has been said that, "If a nation saves its trees, the trees will save the nation." The truth of this assertion is apparent in many parts of the world today. In South Africa, fires and demands in the past for timber have led to extensive depletion of the Natural Forests. In many cases, natural revegetation has been slow to develop and deterioration of the soil has resulted. The desire to replace the tree cover and at the same time to meet an increasing internal demand for timber, has led to widespread planting of Pine and Bluegum. It is probable that more trees have now been planted than were destroyed in the past. The silviculturist however, who develops a pure stand on land which previously supported the mixed stand, should anticipate a change in soil properties as a natural accompaniment of such an undertaking. The nature of this change is the primum mobile of the present comparative study. The forest soils studied were taken in the Cape Province in the following areas:- Grahamstown; Amatola Mountains, District Alice; Witte-els-Bosch, District Humansdorp, during the course of a year. The physical and chemical properties, and the faunal composition of the soil samples were examined in relation to the different tree covers. Because of the necessity of taking large numbers of samples and thorough examination of these to arrive at a definite conclusion, the work is necessarily incomplete. It is felt however that the results obtained justify a further study of this aspect of soil biology.
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The distribution, importance and biology of the important cotton pests of Moc̦ambique

- Da Silva Barbosa, António Jorge

Authors: Da Silva Barbosa, António Jorge
Date: 1952
Subjects: Cotton -- Diseases and pests -- Moc̦ambique
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5844 , http://hdl.handle.net/10962/d1010977 , Cotton -- Diseases and pests -- Moc̦ambique
Description: Up to the second half of the eighteenth century the most important fibres in the world were wool, flax and silk. But the Industrial Revolution in England, together with the invention of the Cotton gin by Whitney in 1793, soon gave cotton the first place amongst all the important fibers in world's textile industry. Although some attempts were made, both in Angola and Mozambique to cultivate cotton since remote days -- as far back as the American Civil War, when market prices suffered an important rise no serious efforts were made to grow this crop before the proclamation of the Portuguese Republic in 1910, when some definite legislation was passed to encourage the development of this culture.
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