328 



NA TURE 



[January 13, 1910 



petition. .The Council is prepared to award in 1910 not 

 more tlian fifteen scholarships in science and technology, 

 consisting of free education at recognised polytechnics, 

 technical institutes, or institutions of university rank, 

 together with, in cases where the Council thinks fit, main- 

 tenance grant, to be fixed after consideration of the circum- 

 stances of each candidate, but not to exceed 50/. a year 

 in any case, and to be tenable for a period of two years, 

 with a possible extension for a third year. The scholar- 

 ships will be open to persons engaged in industrial pur- 

 suits who have attended evening classes at polytechnics, 

 technical institutes, or colleges of university rank. Also 

 not more than 180 evening exhibitions in science and 

 technology, to be open to persons engaged in or intending 

 to engage in industry, each exhibition to consist of pay- 

 ment of tuition fees, together with a grant of 3?. a year, 

 and to be tenable for two years, with a possible extension 

 fora third year. Full particulars of the conditions under 

 which the awards will be made are contained in a pam- 

 phlet to be obtained from the L.C.C. education ofiicer. 

 There will be two distinct compeitions, viz. Classes A 

 and B. Candidates for the scholarships must compete i 

 under Class B ; those for the exhibitions may compete 

 under either Class A or Class B. The teachers' reports 

 will also be taken into account. The award of exhibitions 

 by the competition in Class A will be confined to candi- 

 dates who, in the case of boys, are less than eighteen, 

 an'd, in the case of girls, are less than nineteen, years of 

 age on July 31, loio, and have attended classes in the 

 subjects which they offer for examination for not less 

 than 150 registered hours during the two previous school 

 years at one of the Council's evening schools or evening 

 centres. _ These candidates will be required to take an 

 examination to bo conducted by the Council in certain 

 subjects of general education. Candidates in Class B may 

 compete in either of two ways, by entering for an ex- 

 amination in two subjects, or by submitting works and 

 also undergoing a test examination in one subject. The 

 principals and headmasters or headmistresses of the institu- 

 tions or schools at which the candidates are in attendance 

 will be asked to submit full reports on their work. In 

 making the award, account will be taken of these reports 

 as well as of the candidates' work in the examination. 

 Fuller particulars of the Council's scholarships, &c., appear 

 in the Council's Scholarships Handbook, published by 

 Messrs. P. S. King and Son, 2 and 4 Great Smith Street, 

 Westminster, S.W., price id. 



SOCIETIES AND ACADEMIES. 



London. 

 Geological Society, Decemi>er 15, 190Q.— Prof. W. J. 

 SoUas, F.R.S., president, in the chair.— R. H. Rastall : 

 The Skiddaw granite and its metamorphism. The visible 

 exposures of the Skiddaw granite are three in number, all 

 very similar; part of the more northerly one is a grei'sen, 

 which is not here dealt with. The normal granite is more 

 or less porphyritic in structure, with large phenocrysts 

 of perthite, in a coarse- or fine-textured ground-mass of 

 orthoclase, plagioclase, biotite, and muscovite. Evidence 

 IS brought forward to indicate that the granite is intruded 

 along the axis of an anticline, with a strike approximately 

 E. 15° N. and W. 15° S., the normal direction for the 

 district. The metamorphic aureole is very large, measuring 

 about six miles from east to west, and five miles from 

 north to south. This is out of all proportion to the size 

 of the visible exposures of granite, and it is inferred that 

 the intrusion underlies a large area at a small depth. 

 Within this area three distinct rock-types can be recog- 

 nised, namely :— (i) black slates ; (2) grey flags ; (3) grey 

 grits._ The metamorphism produced in each of these is 

 described in detail, and it is shown that the commonly 

 accepted zones of alteration do not hold, since the rock's 

 concerned were originally of very different character. The 

 phenomena displayed may be summed up as an example 

 of a moderate degree of thermal metamorphism, due to 

 the intrusion of a large mass of granite, at a comparatively 

 low temperature, into a series of rocks of variable com- 

 NO. 2098, VOL. 82] 



position, which had previously undergone dynamic meta- 

 morphism. — A. M. Finlayson : The metallogeny of the 

 British Isles. The ore-deposits of the British Isles (tin, 

 copper, lead, zinc, gold) are considered synthetically in 

 their relation to igneous rocks and to tectonics. The great 

 bulk of the deposits of economic importance, including the 

 veins of Cornwall and Devon, the lead, zinc, and copper 

 veins in England, southern Scotland, Wales, and Ireland, 

 are of Hercynian (and Armorican) age. This is shown by 

 the age of the Assuring in many cases (post-Carboniferous 

 to pre-Triassic), by the absence of ore-veins in Jurassic 

 or later formations, and by other evidence. The Tertiary 

 volcanic period was not accompanied by ore-deposition. 

 The ore-deposits are classified according to metallogenelic 

 epochs, and are divided into metallogenetic provinces, as 

 has been done by Prof. L. de Launay with the ore-deposits 

 of Italy, Africa, and Siberia. The essential features of 

 the different groups are summed up. The evidence, 

 collected and sifted, indicates the following zones of ore- 

 deposition : — (i) Pneumatolytic zone : tin, passing up into 

 copper. (2) Deeper vein-zone : copper with gold. Lead 

 and zinc subordinate. (3) Middle and upper vein-zones : 

 lead and zinc. Copper subordinate. The conclusions 

 drawn from the investigation are : — (i) The importance of 

 the physical conditions of the Permo-Trias in favouring 

 ore-deposition in upper zones, (ii) The close connection 

 between metallogenetic and petrographical provinces, and 

 the essential dependence of ore-formation throughout geo- 

 logical time on the differentiation of igneous rocks accom- 

 panying great crustal movements. Differences in ore- 

 deposits in different localities and regions appear to be 

 due to primary differentiation of ores accompanying the 

 differentiation of igneous magmas at successive epochs. — 

 F. P. Mennell : The geological structure of southern 

 Rhodesia. The author describes in some detail a portion 

 of what may be termed " the Laurentian area " of Africa. 

 The oldest rocks include all lithological varieties, and 

 exhibit most of the known types of alteration. They com- 

 prise a great development of hornblendic rocks (epidiorites 

 and amphibolites) ; on the other hand, mica-schists, and 

 sheared rocks generally, are conspicuously absent. They 

 include (i) " basement schists " on which the altered 

 sediments were laid down, and (2) altered basic igneous 

 intrusions, simulating rocks of any previous age. All 

 these are older than the granites by which they, and the 

 metamorphic series, are invaded. The vertically bedded 

 " ironstone series " is described, and is compared with 

 similar rocks of the Lake Superior region. They are 

 shown to be especially developed along the eastern border 

 of Matabeleland. The conglomerate beds (or Rhodesian 

 " banket ") are 10,000 feet thick, and rest unconformably 

 upon the ironstone series in the west, both these forma- 

 tions being gold-bearing. The thick crystalline limestones 

 overlying the conglomerate series contain chert and dolo- 

 mite, the latter rock occurring also as an alteration pro- 

 duct from serpentine. Graphite also is found, and is 

 attributed to the insolubility of carbonaceous matter in a 

 highly siliceous magma. The granites occupy the greater 

 part of the area dealt with, and their intrusive character 

 as regards the metamorphic rocks is shown. No fossils 

 are recorded, other than silicified wood, except in the 

 coal-bearing beds, in which occurs Palaeomulela keyser- 

 lint;i of the Russian Permian, as also plants. The paper 

 concludes with a description of the diamond-bearing beds 

 of Rhodesia, which resemble those of Kimberley, and also 

 contain fragments of eclogite. 



Royal Microscopical Society, December 11;, igog. — Mr. 

 E. J. Spitta, vice-president, in the chair. — A. A. C. E. 

 Merlin : The measurement of Grayson's 10 band plate. 

 — Dr. M. Ewelt : A convenient form of stand for use as 

 a micro-colorimeter and with micro-spectroscope. — Dr. 

 J. F. Gemmell : .An automatic aerating apparatus for 

 aquaria. — F. Enock : The life-history of the Hessian fly, 

 with notes on the Tenby wheat midge. Although known 

 in America so far back a? 1776, and believed to have 

 been introduced there in the straw mattresses of some 

 Hessian troops, it was not until 1886 that public attention 

 was directed to the Hessian fly in this country. The 

 fallacies then circulated were described and corrected, and 



