5 results for 1930, Doctoral

  • The Puketi Kauri forest : an attempt to apply the quadrat method to the ecological study of the Kauri forest

    Latter, H. B. (1933)

    Doctoral thesis
    University of Canterbury Library

    At present there is no accurate quantitative knowledge of the composition of the kauri bush. This must be obtained so that when the kauri bush is put under a system of management it may be known how far the natural composition has been departed from. To make accurate comparisons possible between virgin bush and silviculturally treated stands, a quantitative ecological description is needed to supplement the ordinary qualitative description. The quadrat accompanied by a cross section is an attempt to supply this. Supposing a kauri forest is under management and is being brought into the condition of the so/called ‘normal’ forest, it is desirable to compare all the age classes of this forest with the corresponding age classes in the virgin forest for reasons which follow.

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  • The hydrolysis of salts of weak acids and weak bases

    Skelton, P. R. (1930)

    Doctoral thesis
    University of Canterbury Library

    It has shown, from theoretical considerations, by R. O. Griffiths (Trans. Faraday Soc. 17,525, 1922) that the classical derivation of an equation connecting the degree of hydrolysis of salts formed from weak acids and weak bases with the dissociation constants of the acid and base respectively, is based on an assumption which in valid for moderately dilute solutions and for moderately weak acids and bases only. In very dilute solutions, or when the acid or base is very weak, the classical equation breaks down. Tizard’s deduction (Trans. Chem. Soc. 97, p.2477, 1910) that the concentration of hydrogen ions in a solution of a weak salt is constant, whatever the dilution, is, for the same reason, in error when the concentration is very low, or when hydrolysis is nearly complete. In the classical treatment it is assumed that, on the hydrolysis of a weak salt (B.A.) the concentration of free undissociated acid, and of free undissociated base in solution are equal, the ionisation of these two components being regarded as negligible, wherein lies the fallacy. The existence of the above erroneous assumption in the classical treatment has also been pointed out by E.W. Hullett (in a thesis presented last year – as yet unpublished). Hullett arrived at the same conclusions as Griffiths (loc. cit.) but, whereas Griffiths merely showed the necessity for defining the degree of hydrolysis of a weak salt more explicitly, Hullett did assign a definite meaning to the degree of hydrolysis, and, moreover, derived equations with which, from electrometric measurements of hydrogen ion concentration, and from knowledge of the dissociation constant of either acid or the base, it is possible to calculate the degree of hydrolysis of weak salt.

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  • Photo electric theory and technique and its application to astronomical research

    Glover, P. W. (1930)

    Doctoral thesis
    University of Canterbury Library

    Modern theory regards light as an electromagnetic disturbance and a change in electrification as the removal or addition of electrons which are negatively charged. Hence a photo electric change can be considered as the liberation of some of these negative electrons by the action of electro magnetic waves. Hertz in 1887 found that ultra-violet light falling on a spark gap caused the discharge across that gap to be made more easy, and that the effect was proportional to the actinic quality of the light source used. In 1888, Wiedmann and Ebert proved that the phenomenon takes place at the cathode of the spark gap. The “Hallwachs Effect” was discovered in the same year (1888). W. Hullwachs found that ultra violet light falling on a body carrying a charge of negative electricity caused that body to lose its charge of negative electricity very readily, but that ultra violet light falling on a positively charged body does not cause the charge to be liberated. Here then we have a difference between positive and negative electrification. Hallwachs showed later that if a body, carefully insulated and initially free from electrical charge, be exposed to ultra violet light, it requires a positive charge. The experimental methods of studying the photo electric discharge was as follows: The brightly polished metal plate which received the illumination formed one plate of an air condenser, of which the other plate, likewise polished was positively charged by means of a battery, and the continuous currant produced was measured by means of an electrometer. For a condenser constructed of a certain metal, it was found that beyond a certain potential difference, this current became independent of the field, and this saturation current could then be regarded as a measure of the photo electric activity of that metal. It was found by Elster and Geitel that the photo electric effect was more pronounced the more electro positive the body, Rubidium for example losing a negative charge when illuminated by light from a glass rod heated to redness.

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  • A study of the heats of reaction of the binary mixture ether - chloroform

    Wilson, F. J. (1934)

    Doctoral thesis
    University of Canterbury Library

    The reasons causing temperature and volume changes due to the mixing of non-aqueous liquids are varied. The phenomenon is probably complex because of the processes that may happen during true solution such as association, disassociation, chemical combination and thermal deassociation. Should these processes become superimposed then investigation of the main reasons become complicated. As one of the most important accompaniments of a spontaneous chemical combination is the production of heat it seems justifiable to assume that where heat derivation is great, then chemical combination many be taken as a primary cause of the heat change and its aspects should be worth studying. A notable example is the binary mixture ether-chloroform and the work described in the following pages as undertaken with the object of finding out what factors affect the heats of reaction of this mixture, and whether it is possible to determine from the measurements of this property, the composition of a compound that might exist in a liquid mixture containing these constituents. In the past other properties have been studied especially physical properties, with the object of elucidating the nature of the compound or compounds formed on the admixture of non-aqueous liquids, as well as this thermal property which occurs so frequently on mixing. This from freezing point measurements Wyatt (1) confirmed Smits and Berckmans (2) experiments which included the existence of four separate compounds of ether and chloroform at low temperatures. As to whether these compounds existed in the liquid state at the temperatures worked at in the experiments on the heats of reaction could only be proved by an examination of the results obtained. One compound these experiments obtained, that at equimolecular proportions of the two constituents, was of particular interest as this mixture gave in the preliminary experiments the greatest heat effect.

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  • Public opinion in Canterbury on the abolition of the provinces, 1873-6

    Muirhead, P. A. (1936)

    Doctoral thesis
    University of Canterbury Library

    “The degree to which public opinion will actually approximate rational and critical social judgment upon vital issues will depend upon such general conditions in the social population as homogeneity, social equality, education and literacy, objective research for facts and expert guidance, freedom of expression, possibly of publicity, and freedom in inter-communication.” The aim of this work is to describe the attitude of the Canterbury public towards the question or the abolition of the provinces. For purposes of clarity and continuity I have dealt with the subject in three parts - the position up till 1874, the abolition proposals and their reception in Canterbury, and the final stages of provincialism with some notice of its political successor, the county system. The Introduction is somewhat lengthy and detailed, but this is necessary for the understanding of the situation in 1873. The authorities I have used in preparing this study are listed in the bibliography on Page 126. Although a number of chapters centre on the sessions of the Canterbury, Provincial Council and the General Assembly, at all times I have discussed only legislation which affected the attitude ultimately adopted by the people of the Province towards the provincial system. For the reaction of the public towards the measures carried through in the Provincial Council and in the General Assembly public meetings, and the addressee of representatives to their constituents, I have relied mainly on the newspapers “The Lyttelton Times”, and “The Press.” The Provincial council did not publish a report of its debates, but only minutes or its proceedings. The attitude or the municipalities, the outlying districts, the runholders and the newspapers has been discussed in some detail. From the inauguration of the provincial system there were in Canterbury, and in New Zealand as a whole, two parties, provincialist and centralist; and the events and conditions, economic, social and political, of the years 1873-6 were really the culminating factors in the struggle between these two parties, and the ultimate success of the centralists.

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