402 



NATURE 



[January i8. 



Geological Society, December ao, 191 1.— Prof. W. W, 

 Watts, F.R.S., president, in the chair. — Rev. E. Hill : 

 The tjlacial gection« nt Sudbury (Suffolk). The sccttonii 

 round Sudbury were described in two Geological Survey 

 .Vfcmuirs : since the date of pul>lication of thcM much 

 more has been disclosed. A list is given of the principal 

 sections now existing, with references to the descriptions 

 in the Survey .Memoirs and notes of those that arc there 

 undescribed. The paper gives an account of a scries of 

 sands and silts which lie at about 300 O.D. on each side 

 of the present Stour Valley. They seem to indicate 

 shallow-water conditions at a level more than 100 feet 

 above the present valley-floor. On the silts lies Chalky 

 Boulder Clay. The transition from silt to clay is con- 

 tinuous, and seems to show that here the transition from 

 formation of silt to formation of Boulder Clay was a 

 continuous transition. The undisturbed condition of the 

 beds indicates that during this transition there was no 

 action of thrust or drag. \\. lower levels, from 180 O.D. 

 down to 100 O.D., on the flanks of the valley lie coarse 

 gravels and sands, with current-bedding, which point to 

 torrential water-action. Among these occur displaced 

 masses of previously formed Boulder Clay, some conhjrted 

 — as if by slip down slopes. At Little Cornard brick- 

 works there is associated with current-bedded gravels a 

 clay in which are embedded very large masses of remade 

 Chalk. The deduction from these facts is that at Sud- 

 bury Boulder Clay began to be formed where there was 

 quiet water, which stood on both sides of the valley at a 

 level of more than 120 feet above the present floor, and 

 that, after such clay had been formed, there came to be 

 strong currents into or along the valley at various lower 

 levels. These deductions agree with the probable course 

 of events if a submergence preceded the Chalky Boulder 

 Clay and an emergence followed it. — C. I. Qardiner and 

 Prof. S. H. Reynolds : The Ordovician and Silurian 

 rocks of the Kilbride peninsula (County Mayo). The Kil- 

 bride peninsula includes three principal groups of rocks. 

 The northern and western part is, in the main, composed 

 of igneous rocks, contemporaneous and intrusive, of Arenig 

 age ; the southern and eastern part principally consists of 

 Silurian rocks, but these are in the south-eastern corner 

 of the peninsula faulted against an area of gneiss. The 

 Arenig rocks resemble the Mount Partry beds of the 

 Tourmakeady and Glensaul districts in the fact that they 

 include cherts and shaly beds with Didymograptus 

 extcnsus, and in the presence of gritty tuffs and coarse 

 breccias, the latter rocks showing a magnificent develop- 

 ment. No coarse conglomerates, however, occur, and no 

 limestone-breccias or other representatives of the Shangort 

 beds of Tourmakeady and Glensaul, while Arenig sedi- 

 ments of all kinds are very scarce. The most interesting 

 feature of the Arenig rocks is the great development of 

 spilitic lavas, which are commonly associated with cherts 

 and often show good pillow-structure. Their resemblance 

 to the similar rock of the Girvan district is very close. 

 An enormous mass of felsite with large quartz-phenocrysts, 

 and often albite, as also pseudomorphs after rhombic 

 pyroxene, occupies much of the northern part of the 

 peninsula. There is no doubt that it, like the similar 

 masses of Tourmakeady and Glensaul, is of Arenig date. 

 The Silurian rocks consist principally of grits, sandstones, 

 and calcareous flags, and dip with great regularity in 

 directions varying from south to east. The calcareous 

 flags (Finny School beds) are highly fossiliferous, and 

 have yielded more than fifty species, principally of corals 

 and brachiopods, which prove the beds to be of Llandovery 

 age. Ill-preserved sf>ecimens of Mouograptus vomerinus, 

 found in the highest Silurian strata exposed, show that 

 these are of Wenlock age. Dr. Henry Woodward, F.R.S., 

 supplies an appendix giving a description of a new species 

 of Caryocaris. 



Mathematical Society, January 11.— Dr. H. F. Bak-r, 

 president, in the chair. — G. H. Hardy and J. E. Littie- 

 wrood : A new condition for the truth of the converse of 

 Abel's theorem. — A. Cunningham : Mersenne's numbers. 

 — W. H. YounK : Successions of integrals and Fourier 

 series. — W. H. Youngr : Multiple Fourier series. 



Royal Astronomical Society, January 12. — Dr. Dyson, 

 president, in the chair. — H. C. Plummer : Hypothetical 

 parallaxes of the brighter stars of type A. The paper was 



NO. 2203, VOL. 88] 



an investigation of th^* radial velocities of brif^t^r st.: 



in a list furnished by Dr. Campbell. T" 



class A stars near the Milky Way are ^ 



of stars in high latitudes. Thin fact ^. 



of type A have a tendency to move pai 



of the .Milky Way.— F. G. Brown : I 



light in space. For a determination of thit> ;> 



author made use of nebuLc, for, since th. 



Ill diameter, their distances can 



<l Nebubc having a small . 



iiiu'-i 1", on an average, more distant ....... .,.- .... 



objects, however their real diameters may differ. — H. 

 Turnar and F. G. Brown : An example of the use 

 spherical harmonic analysis. The authors showed 

 advantages of this analysis in various astronomical inve 

 gations, and gave an example, which also brought < • 

 the main features of the distribution of brightness <.f 

 nebula; in different parts of the sphere. — W. ' 

 Thackeray: Personality and bisection error of s<' 

 Greenwich transit-circle observers. The author's otj 

 was to obtain a determination of the magnitude cquai 

 in R..A. of the present regular observers with the tras 

 circle. It seems clear that the bisection errors vary w 

 the zenith distance, and these personalities may be ' 

 partly to the eye and partly to the different positions tal. 

 up by the observer, according to the zenith distance of 

 star observed. — C. P. Butler : An account of a new f" 

 of telescope recently constructed in .America. The inst 

 ment was a modification of the principle of the equato: 

 coudi, the polat axis being also hollow, but so large t 

 the observer was actually within it. 



Paris. 



Academy of Sciences, December 26, 191 1. — M Armand 

 Gauticr in the chair. — M. Gouy : A particular case of 

 interkathodic action. — M. de Forcrand : The ethylate- 

 calcium. The product of the action of ethyl alcohol 

 metallic calcium, its hydride, carbide, or nitrid* . N 

 alcoholate of calcium ethylate having the formula 



(C,H,0),Ca + 2C,H,0H. 



When this substance is kept over sulphuric acid it l« 

 ethyl ether and ethylene, until after several years its C' 

 position approximates to (CjHjO)jCa + 5Ca(OHK. I 

 is due to a catalytic action of lime, invariably pi 

 the original compound, on the ethyl alcohol and 

 ethylate. — D. Eg^initis : Observations on Brooks,- ^ 

 (1911c) made at the Observatory of .'\thens. Observai; 

 on the position, magnitude, and appearance of the co: 

 on various dates between .August 23 and September 

 — G. Pick : Parallels, and differential geometry in r. 

 Euclidean space. — Ren6 Qarnier : The simplifications of a 

 class of differential systems of which the general integral 

 has fixed critical points. — G. Kowralewieki : A class of 

 infinitesimal transformations of functional space. — P. 

 Montei : The indeterminate character of a uniform funcr 

 tion in the neighbourhood of its essential points. — .\«' 

 Blondei : Singular values of unsymmetrical nuclei.— 

 Maurice Potron : Some properties of linear substitutions 

 with coefficients >o and their application to the problems 

 of production and wages. — M. Rosenblatt : Algebraic 

 surfaces admitting a discontinuous series of bir.it ional 

 transformations. — E. ^tirr^ : Minimum surfaces generated 

 by circular helices. — Emile Giurgrea : Researches on the 

 Kerr effect " in gases and vapours. .According to Lipp- 

 mann, gases and vapours should, in an electric field, show 

 an effect similar to the " Kerr effect " in solid and liquid 

 dielectrics, resulting in a contraction given by the formula 



At' K - I K- , _ , . ... 



— = „ -.r, the effect bemg proportional to the square 



of the field, and becoming greater as the dielectric constant 

 K of the gas is greater. -An interferential method was 

 used, and the effect expected was produced to a very small 

 extent by vapours having large values of K, for example, 

 C,HjBr,CSj,CCl^, but it could not be elicited in air and 

 CO,, even under 25 atmospheres pressure. — E. Cstenave : 

 Synthesis of complementary colours by means of gratings. 

 One side of a glass plate is ruled with parallel lines 

 alternately green and red, and the other with black lines 

 parallel to the coloured ones. When this plate is viewed 



