Studies on the behaviour of Anomala opacicollis (Pér)
- Authors: Miles, Peter Wallace
- Date: 1954
- Subjects: Anomala -- Behavior -- Zimbabwe , Anomala -- Control -- Zimbabwe , Anomala -- Larvae -- Zimbabwe , Scarabaeidae -- Zimbabwe , Beetles -- Control -- Zimbabwe , Tobacco -- Diseases and pests -- Zimbabwe , Tobacco industry -- Zimbabwe , Insecticides -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5901 , http://hdl.handle.net/10962/d1013514
- Description: [Summary]: The larvae of Anomala opacicollis (Pér), of Melolonthid and of other Rutelid species, attack tobacco in Southern Rhodesia, and are more commonly called "whitegrubs". Whitegrubs are widespread in the sandveld areas where tobacco is grown and, at the Trelawney Station of the Tobacco Research Board of Southern Rhodesia, where this work was done, A. opacicollis was the predominant species. An account o£ the one year life cycle is given. The adults eat the leaves of various indigenous trees and an account of an experiment on the food preferences of A. opacicollis adults is given, and the main food sources in the Trelawney area are listed. An experiment is described which shows that the beetles prefer to lay their eggs in the veld or in manured broken land rather than in normal ploughed lands. The larvae are erratically distributed in lands and experiments on larval movement suggest that this is mainly due to concentration of the larvae at discrete concentrations of organic matter in the soil. The temperature and moisture condition of the top 3" of soil are found to be those which attact the larvae. It is suggested that tho larvae prefer and move to soil which contains the lowest amount of moisture which keeps the soil air spaces saturated. lt appears that the preferred temperature decreases with increasing soil moisture content and it is suggested that this is due to the respiratory requirements of the larvae. Soil pH, compaction and fertiliser content and the presence of plants do not appear to influence larval movements. A theory is developed concerning the mechanism of movements in the soil and it is suggested that, in the absence of a continuous gradient, the speed but not the direction of movement is influenced by conditions to which the larvae are sensitive. Evidence in support of thie theory is given. Studies on the survival of larvae at different soil moisture contents and temperatures show that conditions in the top 3" of soil are not likely to be lethal in spite of the high temperatures and low moisture contents found there. The relation of whitegrub behaviour to agricultural problems is discussed. Other workers published evidence indicating that early ploughed lands were attractive to whitegrubs; this is shown not to be the case and the previous evidence is re-interpreted. Such lands tend to contain concentrations of whitegrubs round the borders. The reason for this is discussed and it is suggested that lands should be ploughed early to confine whitegrub infestations in this manner. Soils low in fertility through repeated cultivation are commonly believed to contain more whitegrubs than virgin soil. However, behaviour studies suggest that it is the activity and not the size of the population which is affected by soil fertility. The time at which tobacco is planted is known to determine the extent of subsequent whitegrub damage. The reason for this is to be found in the life cycle of whitegrubs and the results of an experiment on time of planting in relation to whitegrub damage are given. Some insecticides are shown to be more repellant than others to A. opacicollis larvae and the influence of this fact on the assessment of soil insecticide effectiveness in the field is discussed. Reference is made to a method developed by the writer for the determination of insecticide effectiveness under the conditions of erratic whitegrub distribution which normally occur.
- Full Text:
- Date Issued: 1954
- Authors: Miles, Peter Wallace
- Date: 1954
- Subjects: Anomala -- Behavior -- Zimbabwe , Anomala -- Control -- Zimbabwe , Anomala -- Larvae -- Zimbabwe , Scarabaeidae -- Zimbabwe , Beetles -- Control -- Zimbabwe , Tobacco -- Diseases and pests -- Zimbabwe , Tobacco industry -- Zimbabwe , Insecticides -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5901 , http://hdl.handle.net/10962/d1013514
- Description: [Summary]: The larvae of Anomala opacicollis (Pér), of Melolonthid and of other Rutelid species, attack tobacco in Southern Rhodesia, and are more commonly called "whitegrubs". Whitegrubs are widespread in the sandveld areas where tobacco is grown and, at the Trelawney Station of the Tobacco Research Board of Southern Rhodesia, where this work was done, A. opacicollis was the predominant species. An account o£ the one year life cycle is given. The adults eat the leaves of various indigenous trees and an account of an experiment on the food preferences of A. opacicollis adults is given, and the main food sources in the Trelawney area are listed. An experiment is described which shows that the beetles prefer to lay their eggs in the veld or in manured broken land rather than in normal ploughed lands. The larvae are erratically distributed in lands and experiments on larval movement suggest that this is mainly due to concentration of the larvae at discrete concentrations of organic matter in the soil. The temperature and moisture condition of the top 3" of soil are found to be those which attact the larvae. It is suggested that tho larvae prefer and move to soil which contains the lowest amount of moisture which keeps the soil air spaces saturated. lt appears that the preferred temperature decreases with increasing soil moisture content and it is suggested that this is due to the respiratory requirements of the larvae. Soil pH, compaction and fertiliser content and the presence of plants do not appear to influence larval movements. A theory is developed concerning the mechanism of movements in the soil and it is suggested that, in the absence of a continuous gradient, the speed but not the direction of movement is influenced by conditions to which the larvae are sensitive. Evidence in support of thie theory is given. Studies on the survival of larvae at different soil moisture contents and temperatures show that conditions in the top 3" of soil are not likely to be lethal in spite of the high temperatures and low moisture contents found there. The relation of whitegrub behaviour to agricultural problems is discussed. Other workers published evidence indicating that early ploughed lands were attractive to whitegrubs; this is shown not to be the case and the previous evidence is re-interpreted. Such lands tend to contain concentrations of whitegrubs round the borders. The reason for this is discussed and it is suggested that lands should be ploughed early to confine whitegrub infestations in this manner. Soils low in fertility through repeated cultivation are commonly believed to contain more whitegrubs than virgin soil. However, behaviour studies suggest that it is the activity and not the size of the population which is affected by soil fertility. The time at which tobacco is planted is known to determine the extent of subsequent whitegrub damage. The reason for this is to be found in the life cycle of whitegrubs and the results of an experiment on time of planting in relation to whitegrub damage are given. Some insecticides are shown to be more repellant than others to A. opacicollis larvae and the influence of this fact on the assessment of soil insecticide effectiveness in the field is discussed. Reference is made to a method developed by the writer for the determination of insecticide effectiveness under the conditions of erratic whitegrub distribution which normally occur.
- Full Text:
- Date Issued: 1954
The chemistry of naturally occurring long chain unsaturated compounds
- Authors: Silk, M H
- Date: 1954
- Subjects: Compounds, Unsaturated
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4518 , http://hdl.handle.net/10962/d1014332
- Description: [From Introduction, p. 3] Raw marine oils are subject to considerable variation in composition with season and are moreover very unbalanced oils for direct use in the paint industry. Further refining is undertaken chiefly by Messrs Marine Oil Refiners of Africa Ltd., whose factory is situated at Simonstown. In their plant marine oils and others are treated by the Solexol process involving counter current extraction of the oil with liquid propane in a tower over which a temperature gradient is maintained. The process achieves the removal of a large proportion of the relatively saturated glycerides, the natural antitioxidants, and the relatively highly unsaturated components, all of which are detrimental to the eventual formation of good paint films. The segregated marine oil from the Solexol process is then bodied or polymerised at high temperatures to yield a "drying oil" which is used as a substitute for bodied linseed oil in paints. The chemical reactions taking place during the polymerisation and drying of these oils are of an exemely complex nature, and for their understanding it is necessary to have an accurate knowledge of the chemical nature of the component fatty acids in the natural glycerides ... The term "marine oils" in this work should be understood to mean marine fish body oils, marine mammal oils being excluded from consideration.
- Full Text:
- Date Issued: 1954
- Authors: Silk, M H
- Date: 1954
- Subjects: Compounds, Unsaturated
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4518 , http://hdl.handle.net/10962/d1014332
- Description: [From Introduction, p. 3] Raw marine oils are subject to considerable variation in composition with season and are moreover very unbalanced oils for direct use in the paint industry. Further refining is undertaken chiefly by Messrs Marine Oil Refiners of Africa Ltd., whose factory is situated at Simonstown. In their plant marine oils and others are treated by the Solexol process involving counter current extraction of the oil with liquid propane in a tower over which a temperature gradient is maintained. The process achieves the removal of a large proportion of the relatively saturated glycerides, the natural antitioxidants, and the relatively highly unsaturated components, all of which are detrimental to the eventual formation of good paint films. The segregated marine oil from the Solexol process is then bodied or polymerised at high temperatures to yield a "drying oil" which is used as a substitute for bodied linseed oil in paints. The chemical reactions taking place during the polymerisation and drying of these oils are of an exemely complex nature, and for their understanding it is necessary to have an accurate knowledge of the chemical nature of the component fatty acids in the natural glycerides ... The term "marine oils" in this work should be understood to mean marine fish body oils, marine mammal oils being excluded from consideration.
- Full Text:
- Date Issued: 1954
The determination of the solubility of mercurous chloride at 25°C
- Authors: Dry, Mark Eberhard
- Date: 1954
- Subjects: Mercuric chloride
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4463 , http://hdl.handle.net/10962/d1011576 , Mercuric chloride
- Description: After the publication of the paper by Gledhill and Malan in which precision conductance techniques were used for the first time in the determination of the solubility of silver chloride, Dr. N.H. Perton of Christchurch College, New Zealand, wrote to Gledhill and suggested that the same methods might be rewarding if applied to the determination of the solubility of mercurous chloride. A review of the Chemical literature showed that the values for the solubility of mercurous chloride were not at all consistent. Into., p. 1
- Full Text:
- Date Issued: 1954
- Authors: Dry, Mark Eberhard
- Date: 1954
- Subjects: Mercuric chloride
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4463 , http://hdl.handle.net/10962/d1011576 , Mercuric chloride
- Description: After the publication of the paper by Gledhill and Malan in which precision conductance techniques were used for the first time in the determination of the solubility of silver chloride, Dr. N.H. Perton of Christchurch College, New Zealand, wrote to Gledhill and suggested that the same methods might be rewarding if applied to the determination of the solubility of mercurous chloride. A review of the Chemical literature showed that the values for the solubility of mercurous chloride were not at all consistent. Into., p. 1
- Full Text:
- Date Issued: 1954
The polarographic determination of trace elements in blister and refined copper
- Authors: Eve, Adrian John
- Date: 1954
- Subjects: Copper , Polarographs , Polarography
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4467 , http://hdl.handle.net/10962/d1011769 , Copper , Polarographs , Polarography
- Description: In the complete analysis of copper the following impurities are generally determined: silver, gold, lead, arsenic, antimony, selenium, tellurium, iron, zinc, cobalt, nickel, oxygen, sulphur, and, less commonly, tin and phosphorus. The actual copper content varies around 99.0% in blister copper; in the refined metal the content is somewhat higher, usually over 99.9%. The concentrations of the individual impurities vary from tenths to thousandths of one per cent.
- Full Text:
- Date Issued: 1954
- Authors: Eve, Adrian John
- Date: 1954
- Subjects: Copper , Polarographs , Polarography
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4467 , http://hdl.handle.net/10962/d1011769 , Copper , Polarographs , Polarography
- Description: In the complete analysis of copper the following impurities are generally determined: silver, gold, lead, arsenic, antimony, selenium, tellurium, iron, zinc, cobalt, nickel, oxygen, sulphur, and, less commonly, tin and phosphorus. The actual copper content varies around 99.0% in blister copper; in the refined metal the content is somewhat higher, usually over 99.9%. The concentrations of the individual impurities vary from tenths to thousandths of one per cent.
- Full Text:
- Date Issued: 1954
The rehabilitative value of sub-economic housing as illustrated by Schauder Township, Port Elizabeth, Cape Province, Union of South Africa, 1938-1948
- Authors: Stoker, F M L
- Date: 1954
- Subjects: Housing rehabilitation -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3389 , http://hdl.handle.net/10962/d1014554
- Description: [From Introductory discussion]. The modern approach to any sociological problem is characterised by the attempt to analyse the contributory factors in such a way that their inter-active association is clearly discernible. The simple concept of "single cause and effect" is now recognised to be a traversity of social fact. Social Pathology, therefore, may be said to attempt to isolate the multiple factors involved in a given situation, and to endeavour to determine thelr mode of inter-action in order that remedial techniques may be applied effectively. Slum conditions are obviously pathologic, by which it is understood that the environment imposes strains upon the individual to which there is ineffective adjustment. The rehabilitation of such a population would involve the converse process, restoring individuals to a condition where they are able to cope in every respect with the demands of life at their respective class levels. It is very rare indeed that only a single factor is involved in a social pathological condition and for this reason it is quite possible that one- sided efforts at rehabilitation - such as the attempt to re-house ALL slum dwellers in sub-economic houses - have a tendency to increase the pathology in another direction. Rehabilitation must therefore be based on multi-factorial analysis in which allowance is, as far as possible, made for the inter-connection of each of the individual deviations from the normal. The aim of this thesis is to evaluate the effect of good housing conditions on the 2335 Coloured slum families re-housed in sub-economic houses at Schauder Township, Port Elizabeth, from the time that these houses were first available for occupancy.
- Full Text:
- Date Issued: 1954
- Authors: Stoker, F M L
- Date: 1954
- Subjects: Housing rehabilitation -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3389 , http://hdl.handle.net/10962/d1014554
- Description: [From Introductory discussion]. The modern approach to any sociological problem is characterised by the attempt to analyse the contributory factors in such a way that their inter-active association is clearly discernible. The simple concept of "single cause and effect" is now recognised to be a traversity of social fact. Social Pathology, therefore, may be said to attempt to isolate the multiple factors involved in a given situation, and to endeavour to determine thelr mode of inter-action in order that remedial techniques may be applied effectively. Slum conditions are obviously pathologic, by which it is understood that the environment imposes strains upon the individual to which there is ineffective adjustment. The rehabilitation of such a population would involve the converse process, restoring individuals to a condition where they are able to cope in every respect with the demands of life at their respective class levels. It is very rare indeed that only a single factor is involved in a social pathological condition and for this reason it is quite possible that one- sided efforts at rehabilitation - such as the attempt to re-house ALL slum dwellers in sub-economic houses - have a tendency to increase the pathology in another direction. Rehabilitation must therefore be based on multi-factorial analysis in which allowance is, as far as possible, made for the inter-connection of each of the individual deviations from the normal. The aim of this thesis is to evaluate the effect of good housing conditions on the 2335 Coloured slum families re-housed in sub-economic houses at Schauder Township, Port Elizabeth, from the time that these houses were first available for occupancy.
- Full Text:
- Date Issued: 1954
A critical study of methods for the determination of zinc in soils and plant materials
- Authors: Eve, Desmond John
- Date: 1955
- Subjects: Soils -- Zinc content , Soils -- Analysis , Plants -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4468 , http://hdl.handle.net/10962/d1011770 , Soils -- Zinc content , Soils -- Analysis , Plants -- Analysis
- Description: Although it is only fairly recently that the importance of trace elements in plant nutrition has been established, enormous advances have been made in this field of research and numerous publications of considerable scientific and economic importance, dealing with the subject, have appeared. The physiological functions of zinc in promoting plant growth have not all been satisfactorily identified as yet. There are indications, however, that zinc acts as a catalyst or regulator in plant metabolism. It appears too, that the element plays some role in chlorophyll formation. Zinc deficiency is associated with leaf chlorosis and a general collapse of v ital processes. The analysis of leaves and soils has become an essential part of the study of the nutritional diseases of plants and it is imperative that accurate and reliable methods of analysis should be available. Intro. p. 1.
- Full Text:
- Date Issued: 1955
- Authors: Eve, Desmond John
- Date: 1955
- Subjects: Soils -- Zinc content , Soils -- Analysis , Plants -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4468 , http://hdl.handle.net/10962/d1011770 , Soils -- Zinc content , Soils -- Analysis , Plants -- Analysis
- Description: Although it is only fairly recently that the importance of trace elements in plant nutrition has been established, enormous advances have been made in this field of research and numerous publications of considerable scientific and economic importance, dealing with the subject, have appeared. The physiological functions of zinc in promoting plant growth have not all been satisfactorily identified as yet. There are indications, however, that zinc acts as a catalyst or regulator in plant metabolism. It appears too, that the element plays some role in chlorophyll formation. Zinc deficiency is associated with leaf chlorosis and a general collapse of v ital processes. The analysis of leaves and soils has become an essential part of the study of the nutritional diseases of plants and it is imperative that accurate and reliable methods of analysis should be available. Intro. p. 1.
- Full Text:
- Date Issued: 1955
A sample survey of farming types in the divisions of Albany and Bathurst
- Authors: Davies, R J
- Date: 1955
- Subjects: Agriculture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4885 , http://hdl.handle.net/10962/d1014733
- Description: [From Introduction]. It is the purpose of this thesis to examine some of the broad relationships which exist between different land use types and farming practises on the one hand and the geographical environment on the other. The enquiry is confined to the study of a number of farm units which have been selected within the area enclosed by the District of Albany and Bathurst situated in the south-East coastal belt of the Cape Province. The procedure adapted conforms broadly to that of a project carried out in South America by R.S. Platt of the University of Chicago and embodied in hls book "Latin America, Countryside and United Regions." Platt's project, he notes, consists of a collection of "small field studies in a frame of complex generalisations." It does not aim to give a complete geographical account of the regions he selected for investigation, but is an attempt to enlarge geograpical understanding of the respective areas.
- Full Text:
- Date Issued: 1955
- Authors: Davies, R J
- Date: 1955
- Subjects: Agriculture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4885 , http://hdl.handle.net/10962/d1014733
- Description: [From Introduction]. It is the purpose of this thesis to examine some of the broad relationships which exist between different land use types and farming practises on the one hand and the geographical environment on the other. The enquiry is confined to the study of a number of farm units which have been selected within the area enclosed by the District of Albany and Bathurst situated in the south-East coastal belt of the Cape Province. The procedure adapted conforms broadly to that of a project carried out in South America by R.S. Platt of the University of Chicago and embodied in hls book "Latin America, Countryside and United Regions." Platt's project, he notes, consists of a collection of "small field studies in a frame of complex generalisations." It does not aim to give a complete geographical account of the regions he selected for investigation, but is an attempt to enlarge geograpical understanding of the respective areas.
- Full Text:
- Date Issued: 1955
A study of certain aspects of the Mount Coke Missionary Institution
- Authors: Walker, James Andrew
- Date: 1955
- Subjects: Shaw, William, 1798-1872 , Missions -- South Africa -- Eastern Cape , Missionaries -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1282 , http://hdl.handle.net/10962/d1013463
- Description: In searching for information concerning the chain of stations that William Shaw established from the Eastern Frontier of the Cape Colony towards Natal, I found that I had to consult many books. Many sources of information have recently come to light and this had to be analysed as well. In this work much had to be included that did not directly refer to Mount Coke, but it is relevant in that it affected the history of the Mission, and the effect of the Mission on the community as a whole. When histories of all the stations are written the incidents should show up in the right perspective.
- Full Text:
- Date Issued: 1955
- Authors: Walker, James Andrew
- Date: 1955
- Subjects: Shaw, William, 1798-1872 , Missions -- South Africa -- Eastern Cape , Missionaries -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1282 , http://hdl.handle.net/10962/d1013463
- Description: In searching for information concerning the chain of stations that William Shaw established from the Eastern Frontier of the Cape Colony towards Natal, I found that I had to consult many books. Many sources of information have recently come to light and this had to be analysed as well. In this work much had to be included that did not directly refer to Mount Coke, but it is relevant in that it affected the history of the Mission, and the effect of the Mission on the community as a whole. When histories of all the stations are written the incidents should show up in the right perspective.
- Full Text:
- Date Issued: 1955
An investigation into the insect ecology of citrus orchards, with special reference to citrus mussel scale (Lepidosaphes beckii newm.)
- Carnegie, Alistair John Michael
- Authors: Carnegie, Alistair John Michael
- Date: 1955
- Subjects: Citrus -- Diseases and pests -- South Africa -- Eastern Cape , Lepidosaphes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5905 , http://hdl.handle.net/10962/d1014637
- Description: In the course cf the last fifteen years the general lnsect ecology of citrus orchards in the Eastern Cape has provided the subject matter of four theses presented for the degree of M.Sc. of Rhodes University. The false codlin moth, Argyroploce leucotreta Meyr., formed the subject of a thesis by Horne in 1939. Then in 1941 the same insect formed the subject matter of a thesis by Harris. The general ecology of a citrus orchard, with special regard to the biological control of citrus red scale, Aonidiella aurantii Mask., was the subject matter of Whitehead's thesis in 1948. This was a much more general investigation than the preceding two theses, and touched on many more aspects of citrus ecology. Another thesis dealing with more general citrus ecology was that of Smithers in 1953.
- Full Text:
- Date Issued: 1955
- Authors: Carnegie, Alistair John Michael
- Date: 1955
- Subjects: Citrus -- Diseases and pests -- South Africa -- Eastern Cape , Lepidosaphes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5905 , http://hdl.handle.net/10962/d1014637
- Description: In the course cf the last fifteen years the general lnsect ecology of citrus orchards in the Eastern Cape has provided the subject matter of four theses presented for the degree of M.Sc. of Rhodes University. The false codlin moth, Argyroploce leucotreta Meyr., formed the subject of a thesis by Horne in 1939. Then in 1941 the same insect formed the subject matter of a thesis by Harris. The general ecology of a citrus orchard, with special regard to the biological control of citrus red scale, Aonidiella aurantii Mask., was the subject matter of Whitehead's thesis in 1948. This was a much more general investigation than the preceding two theses, and touched on many more aspects of citrus ecology. Another thesis dealing with more general citrus ecology was that of Smithers in 1953.
- Full Text:
- Date Issued: 1955
An investigation of the spectra and decay times of some organic phosphors under ultraviolet and ionising radiation
- Authors: Little, W A
- Date: 1955
- Subjects: Phosphors -- Spectra
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5530 , http://hdl.handle.net/10962/d1012733
- Description: In this thesis I have given an account of the work carried out by me on the measurement of the spectra and decay times of a few selected organic phosphors under ultraviolet and ionising radiation. The purpose of the investigation has been to attempt to throw more light on the mechanism by which energy migrates within the crystalline lattice. A general introduction is given to the process of fluorescence and the various proposed theories by which the excitation energy, which eventually appears as fluorescence light, is able to move about in the crystalline lattice. Preface, p. 1.
- Full Text:
- Date Issued: 1955
- Authors: Little, W A
- Date: 1955
- Subjects: Phosphors -- Spectra
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5530 , http://hdl.handle.net/10962/d1012733
- Description: In this thesis I have given an account of the work carried out by me on the measurement of the spectra and decay times of a few selected organic phosphors under ultraviolet and ionising radiation. The purpose of the investigation has been to attempt to throw more light on the mechanism by which energy migrates within the crystalline lattice. A general introduction is given to the process of fluorescence and the various proposed theories by which the excitation energy, which eventually appears as fluorescence light, is able to move about in the crystalline lattice. Preface, p. 1.
- Full Text:
- Date Issued: 1955
Measurements of the solubilities of some silver halides in water by electrical methods
- Authors: Malan, George McPherson
- Date: 1955
- Subjects: Silver halides -- Solubility , Silver halides -- Analysis , Conductometric analysis , Potentiometry , Silver halides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4515 , http://hdl.handle.net/10962/d1013502
- Description: [Introduction, p. 3] The solubilities of the silver halides cannot be determined by the conventional methods of analytical chemistry because they are too sparingly soluble (of the order 1 x 10⁻⁵ to 1 x 10⁻⁶ g . equiv./1. at 25°C.) However, electrical, and to a lesser extent optical methods, are admirably suited because of their greater sensitivity. The conductometric and potentiometric methods are the two most important electrical techniques for the measurement of the solubilities of sparingly soluble salts, and are the ones employed in this research. There are large discrepancies between the published values for the solubility of silver chloride. Results obtained by the conductometric and potentiometric methods disagree. In addition, figures quoted by independent authors using the same method differ by as much as 15%.
- Full Text:
- Date Issued: 1955
- Authors: Malan, George McPherson
- Date: 1955
- Subjects: Silver halides -- Solubility , Silver halides -- Analysis , Conductometric analysis , Potentiometry , Silver halides
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4515 , http://hdl.handle.net/10962/d1013502
- Description: [Introduction, p. 3] The solubilities of the silver halides cannot be determined by the conventional methods of analytical chemistry because they are too sparingly soluble (of the order 1 x 10⁻⁵ to 1 x 10⁻⁶ g . equiv./1. at 25°C.) However, electrical, and to a lesser extent optical methods, are admirably suited because of their greater sensitivity. The conductometric and potentiometric methods are the two most important electrical techniques for the measurement of the solubilities of sparingly soluble salts, and are the ones employed in this research. There are large discrepancies between the published values for the solubility of silver chloride. Results obtained by the conductometric and potentiometric methods disagree. In addition, figures quoted by independent authors using the same method differ by as much as 15%.
- Full Text:
- Date Issued: 1955
Rhodes University Graduation Ceremony 1955
- Authors: Rhodes University
- Date: 1955
- Language: English
- Type: text
- Identifier: vital:8089 , http://hdl.handle.net/10962/d1004399
- Description: Rhodes University Graduation Ceremony in the Grahamstown City Hall on Friday , 1st April, 1955, at 8 p.m. [and] Graduation Ceremony held in April 1955: University College of Fort Hare. Graduation Ceremony. April 29th ,1955.
- Full Text:
- Date Issued: 1955
- Authors: Rhodes University
- Date: 1955
- Language: English
- Type: text
- Identifier: vital:8089 , http://hdl.handle.net/10962/d1004399
- Description: Rhodes University Graduation Ceremony in the Grahamstown City Hall on Friday , 1st April, 1955, at 8 p.m. [and] Graduation Ceremony held in April 1955: University College of Fort Hare. Graduation Ceremony. April 29th ,1955.
- Full Text:
- Date Issued: 1955
Some problems and methods of measuring the growth of African negroid populations
- Myburgh, Corneles Albert Lloyd
- Authors: Myburgh, Corneles Albert Lloyd
- Date: 1955
- Subjects: Africa -- Population -- Statistics , Demography -- Africa , Population forecasting -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3388 , http://hdl.handle.net/10962/d1013560
- Description: A dissertation ... giving details of problems and methods of obtaining statistics of the more important demographic aspects of the African Negroid populations, that is the size of a population, its sex and age distribution, migration movements, deaths and rates of increase.
- Full Text:
- Date Issued: 1955
- Authors: Myburgh, Corneles Albert Lloyd
- Date: 1955
- Subjects: Africa -- Population -- Statistics , Demography -- Africa , Population forecasting -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3388 , http://hdl.handle.net/10962/d1013560
- Description: A dissertation ... giving details of problems and methods of obtaining statistics of the more important demographic aspects of the African Negroid populations, that is the size of a population, its sex and age distribution, migration movements, deaths and rates of increase.
- Full Text:
- Date Issued: 1955
Studies of Hypnea spicifera
- Authors: Hewitt, Florence E
- Date: 1955
- Subjects: Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4271 , http://hdl.handle.net/10962/d1018234
- Full Text:
- Date Issued: 1955
- Authors: Hewitt, Florence E
- Date: 1955
- Subjects: Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4271 , http://hdl.handle.net/10962/d1018234
- Full Text:
- Date Issued: 1955
The teaching of the Acts of the Apostles concerning the Holy Spirit
- Authors: Woods, B J
- Date: 1955
- Subjects: Bible. Acts , Holy Spirit
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1281 , http://hdl.handle.net/10962/d1013453
- Description: There must be certain reasons why one embarks on a study of the Holy Spirit. The first is perhaps because there is a need today for a Biblical doctrine of the Spirit. The second follows from the first, for there is a need for a deeper knowledge of the Spirit and His work. He is the life-giving Spirit, and we need today to be spiritually alive. The third reason for a study of this kind is that we need a deeper understanding of the power of the Spirit in the affairs of men in the world. We have got away from the idea that God works amongst us through His Spirit, and we tend to think more and more of the achievements of man, and the power of the machine to do as we wish. We need to return to the power of the Spirit, and to be instruments of God's wishes. Finally, our Christianity today, in this country, appears to be so lifeless, so stuck in the groove of routine - the interminable bazaars, money raising efforts, and social half-hours - that we have lost the enthusiasm of first century Christianity, the driving force of the Spirit spurring us on to bring the Gospel of Life to the hungry world. We need in our modern experience and our modern condition, to find the powerful enthusiasm, as a result of the Spirit' s working in us, that the early Christians found when they were filled with Him and worked under His guidance. So we undertake the study of the Spirit among the early Church, in the hope that we too may desire to be filled as the Apostles were filled.
- Full Text:
- Date Issued: 1955
- Authors: Woods, B J
- Date: 1955
- Subjects: Bible. Acts , Holy Spirit
- Language: English
- Type: Thesis , Bachelor , BDiv
- Identifier: vital:1281 , http://hdl.handle.net/10962/d1013453
- Description: There must be certain reasons why one embarks on a study of the Holy Spirit. The first is perhaps because there is a need today for a Biblical doctrine of the Spirit. The second follows from the first, for there is a need for a deeper knowledge of the Spirit and His work. He is the life-giving Spirit, and we need today to be spiritually alive. The third reason for a study of this kind is that we need a deeper understanding of the power of the Spirit in the affairs of men in the world. We have got away from the idea that God works amongst us through His Spirit, and we tend to think more and more of the achievements of man, and the power of the machine to do as we wish. We need to return to the power of the Spirit, and to be instruments of God's wishes. Finally, our Christianity today, in this country, appears to be so lifeless, so stuck in the groove of routine - the interminable bazaars, money raising efforts, and social half-hours - that we have lost the enthusiasm of first century Christianity, the driving force of the Spirit spurring us on to bring the Gospel of Life to the hungry world. We need in our modern experience and our modern condition, to find the powerful enthusiasm, as a result of the Spirit' s working in us, that the early Christians found when they were filled with Him and worked under His guidance. So we undertake the study of the Spirit among the early Church, in the hope that we too may desire to be filled as the Apostles were filled.
- Full Text:
- Date Issued: 1955
Rhodeo, Vol. 8, No. 1
- Date: 1955-03-26
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14438 , http://hdl.handle.net/10962/d1019310
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1955-03-26
- Date: 1955-03-26
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14438 , http://hdl.handle.net/10962/d1019310
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1955-03-26
Rhodeo, Vol. 8, No. 2
- Date: 1955-05-25
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14439 , http://hdl.handle.net/10962/d1019311
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1955-05-25
- Date: 1955-05-25
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14439 , http://hdl.handle.net/10962/d1019311
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1955-05-25
Rhodeo, Vol. 8, No. 3
- Date: 1955-08-17
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14440 , http://hdl.handle.net/10962/d1019312
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1955-08-17
- Date: 1955-08-17
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14440 , http://hdl.handle.net/10962/d1019312
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1955-08-17
Rhodeo, Vol. 8, No. 4
- Date: 1955-09-14
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14441 , http://hdl.handle.net/10962/d1019313
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1955-09-14
- Date: 1955-09-14
- Subjects: Grahamstown -- Newspapers , Journalism, Students -- South Africa , Rhodes University -- Activate , Rhodes University -- Students , Student newspapers and periodicals -- South Africa
- Language: English
- Type: Text
- Identifier: vital:14441 , http://hdl.handle.net/10962/d1019313
- Description: Rhodeo is the Independent Student Newspaper of Rhodes University. Located in Grahamstown, Rhodeo was established in 1947, and renamed in 1994 as Activate. During apartheid Rhodeo became an active part of the struggle for freedom of expression as part of the now defunct South African Student Press Union. Currently Activate is committed to informing Rhodes University students, staff and community members about relevant issues, mainly on campus. These issues range from hard news to more creative journalism. While Activate acts as a news source, one of its main objectives it to be accessible as a training ground for student journalists. The newspaper is run entirely by the students and is published twice a term. Activate is a free newspaper which receives an annual grant from the Rhodes University Student Representative Council, however, majority of its revenue is generated through advertising.
- Full Text:
- Date Issued: 1955-09-14
A preliminary study of adaptation and inhibition of reflex claw opening in the crab Potamon perlatus (Milne Edwards)
- 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.
- Full Text:
- Date Issued: 1956
- 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.
- Full Text:
- Date Issued: 1956