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The Cockburn Law intrusion is situated in that part of Scotland where many intrusions of both Caledonian and Carboniferous age form the Laws of the Lammermuirs. The intrusion has been known for many years and may have been visited by Playfair and Hall during the time of the controversy between the Plutonists and the Neptunists. Cockburn Law, one of the “ Caledonian Granite ” intrusions of the Southern Uplands, lies at the junction of Sheets 33 and 34 of the Geological Survey of Scotland, about three miles north of Duns. The intrusion forms the two hills of Cockburn Law 1,066 ft. O.D. and Stoneshiel Hill 723 ft. O.D. The hills are separated by a gorge formed by a meander in the White- adder Water. The first good description is given by Stevenson (1849), he noticed the variability of the granite and even at that early date attributed the “ marginal ‘ syenites ’ (= diorites) to greywackes fused by the agency of the molten granite F. Walker in two papers (1925) and (1928) described the Cockburn Law intrusion together with other Southern Upland Intrusions. He describes the various rock types present, including a central basic hornblende - biotite - granodiorite, an intermediate ‘ monoclinic - pyroxene-diorite ” and a marginal “ quartz-hypersthene-porphyrite In one paper (1928) F. Walker gave two analyses for the granodiorite and the quartz-biotite-hypersthene-porphyrite. No detailed description of the petrography or of the field relationship of the various rock types is given. The area has been mapped on a 6 in. to 1 mile scale, the mass is not well exposed, in places there are no exposures, being covered with grassland or ploughed land. The best exposures are to be found in the river cliffs of the Whiteadder Water, where it is possible to collect specimens showing the gradual transition of rock types on passing out from the centre of the intrusion. The hybrids are well exposed north of Law Plantation and on the summit of Cockburn Law. There are also fair exposures on the west side of Stoneshiel Hill. The rest is badly exposed, there being only occasional weathered boulders surrounded by grass and heathland. It is nowhere possible to see the transitions in any one exposure. The junction between the intrusion and the Llandovery country rock is not exposed, but it is possible to obtain evidence of the nature of the contact. The intrusion can be divided into two broad groups :— 1. The uncontaminated acid intrusive rocks, adamellite, granite, and granophyric microgranite. 2. The hybrid diorites, resulting from contamination. After consolidation of the main intrusion, continuation of igneous activity produced dykes in the surrounding Silurian rocks, and aplite veins in the main intrusion itself. In this paper the method of formation of the hybrids is indicated, their age in relation to the main body of the intrusion fixed, and the source of material suggested. Variation of the uncontaminated part in relation to the cooling processes of the magma is also explained.

Tests and examinations are used for many different purposes. There is the familiar school class examination, the main object of which is to ascertain how much of the subject taught has been understood and remembered. An examination of a slightly different type is that set for the Leaving Certificate of the Scottish Education Department; although it follows the lines of the ordinary schhol examination, an important point is that it is used to classify the candidates into two categories - those worthy to pass, and those who must be counted as failed. A third type of test is exemplified in the examination set to candidates for posts in the Civil Service; what is important in this test is the order of merit of the leading candidates. The different purposes of these examinations are reflected in the structure of the papers. The examiners, through much experience of their particular type of work, have built up a technique of construction of papers, and this, we venture to say, is largely of the "rule of thumb" type. It is the purpose of the research reported here to seek the theoretical basis of the design and effect of different types of paper.

Increased interest in the wise use of land has focussed attention in recent years on the study of the vegetation of the Western Sudan and the question of progressive desiccation and accelerated soil erosion in Northern Nigeria and in French West Africa has received serious investigation. It is now appreciated that soil deterioration has occurred over large areas of arable land which has been unwisely over-exploited and that accelerated soil erosion does not occur to any extent, (although there is normal soil erosion), in the southern portion of the French Niger Colony and in Northern Nigeria; this is largely because the region is for the most part, an undulating if somewhat elevated plain. The writer was engaged on the investigation of possible desiccation in the Kano and Katsina Provinces and part of Bornu Province in Northern Nigeria and also travelled extensively in Sokoto Province. He has been fortunate in spending several years of service in Northern Nigeria and in having been able to carry out a number of vegetational surveys throughout French West Africa; these included journeys in 1933 from Gao across the Sahara to North Africa, in 1935 from Lagos via Niamey to Dakar, in 1939 from Katsina to Agades and the Bagzan Mountains, in 1943 to the Matamaye area and in January of 1944 from Kano to Zinder and Maradi. The writing of this paper was interrupted for three years during the period of hostilities; the interruption was fortunate. for the writer was able to obtain a wider knowledge of French West Africa with over two years of constant study of it in connexion with his Military duties. French Niger Colony was visited during that period at a number of points on the frontier. The journeys in French West Africa were made specific- :ally to study the vegetation and ecology of the area, of which so much is yet to be learned, so that it might be compared with the vegetation, the land-utilisation and the ecology of Northern Nigeria with its much denser population. The vegetation was plotted continuously on the journeys to Agades and Birnin Konni and to Zinder and Maradi: These with the Gao and Dakar journeys form the basis of the vegetational classification included in this paper. A number of aerial photographs which were taken over Northern Nigeria and Niger Colony are included so as better to illustrate the vegetation types; ground photographs of some of the actual points recorded in the aerial photographs were taken afterwards by the writer for the purpose of comparison. Two supplementary papers are included in the thesis, one on the identification and examination of forest types from aerial photographs, the second on silvicultural and ecological research from which definite data have been obtained.

This collection of 48 publications is divided into four groups which may be labelled 1. Original papers on the vibrational spectra of aromatic systems. These comprise A1 to A25. 2. Studies of em pirical inter-nuclear potential functions B1-6. 3. Vibrational analyses &s an aid to structural analysis 01-14. 4. Instrum entation and techniques DI-3. 1. As is seen from the distribution of papers amongst the groups, most effort has been devoted to a study of aromatic systems, primarily of fluoro-arom atics. The latter offer special unique and advantageous properties for vibrational studies. The objectives of this work and the extent to which they have so far been realised may be summarised as follows. (i) - the establishing of the pattern of fundamental vibrational frequencies. Much effort has been devoted to showing that the assign ments for the various molecular species are consistent with one another. (a6, as, A9, A1 9, A22 etc.). In this context three extremely useful and general rules have been established (A2, A9, A22). All are strictly applicable only to isotopically related systems but have been shown to be remarkably well upheld when the systems compared differ by non isotopic substitution. The ’Inequality Rule’ was first proposed by the writer and D.H. Whiffen (A2). The second rule, the ’Sum Fule’, is a well established rule for isotopic systems, but has been shown (A9) to be very useful outside of its normal realm of applicability as a consequence of linear gradation of bond properties with isotopic substitution. An adaption of the 'Eedlich-Teller Product Rule’ has also been usefully employed in deciding between alternative proposed assignments (A22).

In the late 18th century and the first two decades of the 19th, Spanish seapower in the Pacific was in a state of decline, though it remained strong enough to contribute to the overthrow of the first attempt of the Chileans to liberate their colony from Spain, in 1814. By the time of the second, successful, emancipation of Chile in 1817, the patriots had realised the need for seapower. In that year they took into their service Lord Cochrane, a noted British naval officer then unemployed. Lord Cochrane arrived in Chile at the end of 1818. The squadron at that time is described. With this squadron Lord Cochrane made his first cruise, a reconnaissance in force of the royalist-held Peruvian coast during which Callao was attacked without success. Arising from this reconnaissance, the physical environment of the Mar del Sur is reviewed, together with the state of navigational knowledge. The intention of Lord Cochrane's second cruise, which began in September 1819, was to stage a major attack on Callao. This object was not achieved because of the' squadron's inadequate means and the viceroy's defensive measures, so in December 1819 Lord Cochrane sailed to Valdivia, a fortified city in the south of Chile still in Spanish hands, and captured it by assault in February 1820. There has been same debate about his intentions when he sailed for Valdivia. By early 1820 some of the basic social characteristics of the Chilean navy had emerged and these are examined, firstly from the point of view of the manning of the ships and secondly from the point of view of the problems of discipline and morale that arose. At the same time, the system of naval administration should be examined as its defects and malfunctioning had serious effects on the operating of the squadron, and its efficiency. This data forms the background to the squadron's participation in the liberation of Peru. Initially it played a significant role, firstly by shipping the expedition to Peru and secondly by boarding and taking out of Callao harbour the principal Spanish warship there. These successes were in 1820; in 1821 the squadron's role became less important as the relations between Lord Cochrane and San Martin, the commander-in-chief, deteriorated as a result of the refusal or inability of the latter to pay the squadron. In September 1821 Lord Cochrane seized the Peruvian public funds, allegedly to indemnify the expenses of the squadron, and left Peru. His last cruise, from October 1821 to May 1822, had the object of hunting down the remaining Spanish warships in the Pacific. This cruise here receives its first full account. The cruise completed, though not as successfully as he had hoped, Lord Cochrane returned to Chile. His brief remaining stay in that country was disturbed by difficulties in paying off the ships, disputes with San Martin, and the deteriorating political position of the government. When he received an invitation in November 1822 to take command of the Brazilian navy he accepted, resigned from the Chilean service, and left the country at the beginning of 1823. The dissertation is supplemented by the inventory of the papers in the Dundonald collection which relate to the period of Lord Cochrane's service with Chile. These amount to 2286 items.

A study is made of the features required of a printer capable of producing a visible record of transient data. Particular attention is paid to the output requirements of digital electronic computers. A literature survey of high speed printers, both mechanical and non-mechanical, is given. Two feasibility studies are described, the first of a xerographic printer and the second of a laser printer. A description is given of experimental work in which optical information was printed xerographically at speeds in excess of 5,000 lines per minute. The reasons for discontinuing this line of research are stated. A proposed laser printer is then described together with the experimental work performed to determine the feasibility of the principal process involved. This process, the fusing of powdered ink onto paper, is also considered theoretically in terms of heat transfer. An evaluation is made of the acceptability of the images produced. The areas where further research is required to complete the study to the stage of operational printing are indicated.

The main part of the work described in this thesis is concerned with the determination of the crystal and molecular structure of pteridine by X-ray crystallographic methods. The unit cell dimensions and space group of 'substance P', a dipteridyl derivative of unknown structure were also obtained. An additional paper deals with an investigation of the structure of the cellulose fibre sisal with the electron microscope. Pteridine crystallises in the orthorhombic non-centrosymmetrical space group Pna2 1 (C9 2v), molecules per unit cell. The unit cell dimensions are a = 24.70, b = 3.79, c = 6.32 A. The crystal and molecular structure has been determined with coordinate standard deviations of about 0.03 A from a study of Fourier and Fourier difference syntheses projecting on (010) and (001). The molecule is planar to within 0.06 A and the bond lengths vary between 1.28 and 1.41 A for carbon-nitrogen bonds and between 1.35 and 1.42 A for carbon-carbon bonds. The experimental bond length measurements are compared with molecular orbital calculations and are found to agree to within the limits of the experimental errors. The investigation was hampered by the fact that owing to the nature of the crystals only less than half of the possible reflections could be observed with CuKa radiation. Additional difficulties were caused by the non-centrosymmetrical nature of the one projection which gives good resolution and also by the difficulty of distinguishing between carbon and nitrogen atoms. The peak heights in the final electron density projection on (010) confirm the position of the nitrogen atoms, and the hydrogen atoms are also resolved.

In this paper the different interpretations of the genus Delthyris are discussed, and that given by Schuchert in 1913 is adopted with slight amendment. The species Delthyris elevata, D. crispa, D. elegans (nom. nov% for D. crispa. Hi singer, non Linnæus), and D. tenuilamellata, sp. n., from the British Silurian, are all described and figured. The distinguishing characters of the genera Uncinulus and Uncinulina are pointed out, and Uncinulina is retained with U. fallaciosa as genotype. Rhync/ionella stricklandi and Tere- bratula lewisi are transferred to the genus Uncinulina. Meri- stina tumida (Dalman) is shown to be a synonym of Meristina obtusa (Sowerby). The British Silurian Spirifers can be separated into two groups :—(1) those with longitudinal folds and a transverse ornament of imbricating lameilæ (^ — Delthyris of Dalman) and (2) those with longitudinal folds bearing fine continuous longitudinal striæ {j=Fospirifer of Schuchert). The species referable to both these genera have as a rule been assigned to the genus Spirifer, from which, however, they differ in internal characters.

By an orthodox application of the perturbation theory to the general case of a quantized field, it is shown that the divergence difficulty hitherto encountered arises from a faulty application of the expansion method. The difficulty disappears if the degeneracy of the unperturbed system is properly treated by the method of secular perturbation. Physically, it is shown that this amounts to a rigorous treatment of the radiation reaction.

The deuteration of optically active mandelic acid was investigated by shaking it in a sealed, evacuated tube under various conditions of temperature, and with different catalytic agents. The effect of acid, base, and platinum catalysts was examined, and in each case the degree of exchange occurring in the alpha position of the mandelic acid was correlated with the simultaneous change in its optical activity. The results indicated that with a basic catalyst present, the reaction occurred by a racemisation mechanism, an attacked molecule having an equal chance of retaining its configuration or undergoing an inversion. The platinum-catalysed exchange in acid solution was more complex, with both racemisation and retention mechanisms playing a part. With no catalyst present, racemisation of the acid occured, but without a corresponding exchange. In presence of platinum, the benzene ring, as well as the alpha hydrogen atom, was deuterated. These conclusions were confirmed by resolutions of the deuterated mandelic acid, when the observed deuterium contents of the resolved fractions were found to be in good agreement with the figures calculated assuming the mechanisms postulated for the first part of the experiment. The resolution also showed that alpha hydrogen exchange and nuclear deuteration were quite independent. Mechanisms for the various reactions have been suggested, and involve an Initial ionisation of the alpha hydrogen atom, either on the catalyst surface, or under the influence of a basic catalyst. The racemisation without exchange is considered to occur by a mechanism involving an initial fission of the bond between the alpha carbon atom and the carboxyl group.

The starting material for this investigation consisted of 22.5 kilograms of the dry powdered root of Gelsemium sempervirens, Aiton, and the object of the work was the isolation of the alkaloidal constituents of the root, followed by their chemical investigation. On account of the fact that sempervirine is unstable to heat, and is resinified to a large extent in boiling alcohol, it was decided, after some preliminary experiments, to carry out an extraction first of all with cold rectified spirit, followed by an extraction with boiling alcohol. It was decided also to use the method of separation (14) devised by Sayre for the isolation of gelsemine, sempervirine, and the amorphous alkaloids, and also to attempt the isolation of gelsemicine from the gelsemine mother liquors as described by Chou (15) , with certain small modifications in each case. This was done and the yields of gelsemine and sempervirine were found to be very much larger than those recorded by Sayre, particularly in the case of the latter. This was due, presumably, to the employment of a cold alcoholic extraction. The yield of gelsemine obtained was 0. 13% compared with 0.07% recorded by Sayre (14) and that of sempervirine (as nitrate) was 0.084% compared with 0.026% reported by Sayre. A small quantity of an amorphous alkaloid, not previously reported, was found in the gelsemine fraction, but could not be obtained crystalline. This alkaloid was found to be very slightly soluble in water and alcohol on long heating. The melting point of this amorphous alkaloid is 324d. An amorphous piorate was formed from water but could not be crystallised. On evaporating this alkaloid to dryness with hydrochloric acid a crystalline hydrochloride was formed, melting above 340, but owing to the extreme solubility of this hydrochloride and the small amount available, it was not found possible to prepare a sufficient quantity of the pure material for analysis determinations. Prom the fraction of the amorphous alkaloids called gelsemoidine by Sayre, there has been isolated a crystalline methiodide not previously reported. Analysis figures for this methiodide indicate a formula of either C20H24O3N2. CH3I or C20H22O3N2. CH3I. The melting point of this methiodide suggests its identity with apogelsemine methiodide C20H24O3N2. CH3I (melting points 296-297d. and 295d. respectively), but the determination of its specific rotation would seem to discount this view. The value Moore (11) has found for the specific rotation of apogelsemine methiodide is [x]D+12.4. An attempt was made to repeat, as far as possible, the conditions employed by Moore for apogelsemine methiodide, for the determination of the specific rotation of "gelsemoidine" methiodide. This has, however, been found impossible, the new methiodide being less soluble in water than apogelsemine methiodide has been recorded to be. A saturated solution was used for the determination and a value of [a]20D +3.9 was found. For comparison purposes the specific rotation of gelsemine methiodide was determined, and found to differ slightly from Moore's value. The value found was [a]10D+6.0, compared with that of [a]D +8.9 recorded by Moore(10). These results for gelsemine methiodide are in much closer agreement than those for "gelsemoidine" methiodide and apogelsemine methiodide, and it seems possible that the methiodide isolated from the gelsemoidine fraction is not, in fact, identical with apogelsemine methiodide. This possibility is, to a certain extent, enhanced by the fact that neither Sayre nor the present author were able to obtain "gelsemoidine" hydrochloride in the crystalline state, whereas apogelsemine hydrochloride is a crystalline substance. No attempt was made to prepare apogelsemine methiodide for comparison purposes as, for the isolation of pure apogelsemine, a relatively large expenditure of gelsemine would have been involved. The attempted isolation of gelsemicine was not successful, this fraction consisting of a dark brown tarry material which contained some gelsemine.

The following C1, C10- substituted chloro-nitrosocamphanes have been synthesised: The effect of irradiation with polychromatic red light was determined by both spectrophotometric and polarimetric measurements. The absorption spectra of compounds (b) - (e) showed bathochromic shifts after short exposure while that shown by (a) was hypsochromic. The reinvestigation of the spectra of the previously described chloro-nitrosocamphanes (f) and (g) (R = Me and CH2SO3 H+. Py respectively), also revealed changes in l max. after irradiation. Thus all chloro-nitrosocamphanes investigated showed, to varying degrees, changes in their spectra after irradiation. The Cotton effects and C2- configurations of (a), (b) and (g) were opposite those for the parent camphane (f). The irradiation of (a) and (f) resulted in the rapid inversion of their initially opposite curves of rotatory dispersion with a simultaneous displacement of their spectra in different directions. These observations are interpreted in terms of a 2:2' - mutarotation which gives the diastereoisomer with different molecular constants and hence a different spectrum. The polarimetric and absorption measurements for (b) and (g) however, are not easily reconciled with this hypothesis. Irradiation resulted in much greater increases in absorption on the long-wave side of l max. , while their Cotton effects did not change sign. Indeed for comparable changes in their spectra, the rotation of (b) changed by only 166 compared with the 1460 shown by (f). Various alternative causes of band-shift are discussed and shown by experiment to be untenable. The possibility of Wagner-Meerwein and Nametkin rearrangements induced by light is discussed and shown to provide a qualitative interpretation of the differences in the photo-processes of (b) and (g) on the one hand and (a) and (f) on the other. On this basis, the stereochemistry of the molecules determines the nature of the process. Experiments, in which it was hoped to differentiate between photomutarotation and intramolecular rearrangement in (b) and (g), are described. Although it was shown that, like (f) , the product of irradiation of (b) was isomeric with the starting material, the results of these experiments are inconclusive. The substituted chloro-nitrosocamphanes are shown to be theoretically capable of asymmetric photolysis but with greatly impaired efficiency.