NATURE 



[March 6, 19 19 



is followed by detailed descriptions of the principal 

 mines and deposits, and particulars of the costs, 

 system of working-, conditions of labour, and mining- 

 laws.— C. W. Gudgeon : The Giblin tin lode of Tas- 

 mania. This is a deposit which has so far not been 

 the subject of any published description. Like many 

 another property which has since made good, this 

 lode experienced a chequered career before reaching 

 its present position. The author considers this to be 

 a good example of persistence of ore in depth, 



Manchester. 

 Literary and Philosophical Society, February i8.— Mr. 

 W. Thomson, president, in the chair.— Dr. H. Wilde : 

 The mutual relations of natural science and natural 

 religion.— J. Wilfrid Jackson; (i) "Shell-pockets" on 

 sand dunes on the Wirral coast, Cheshire. The paper 

 consisted of a short account of " shell-pockets " in 

 general, and contained remarks on the age of the 

 buried land surfaces in the neighbourhood. (2) A new 

 Middle Carboniferous Nautiloid (Coelonautilus 

 trapezoidalis). The species is founded upon two 

 specimens : one from the Lower Coal Measures near 

 Colne, erroneously figured by Wild in 1892 as. 

 Nautilus suhsulcatus, the other from the Pendleslde 

 series, Pule Hill, Marsden. The species differs from 

 C. suhsulcatus in several important details, but pre- 

 sents some affinity with C. quadratus. 



Edinburgh. 

 Royal Society, January 20.— Dr. John Home, presi- 

 dent, in the chair. — Prof. Harvey-Gibson and Miss Elsie 

 Horsman : Contributions towards a knowledge of the 

 anatomy of the lower Dicotyledons. U. : The 

 anatomy of the stem of the Berberidaceae.— Also Miss 

 Christine E. Quinlan : Contributions towards a know- 

 ledge of the anatomy of the lower Dicotyledons, 

 in. : The anatomy of the stem of the Calycanthaceae. 

 These two papers are parts of a general investigation 

 into the affinities of the lower Dicotyledons and. the 

 Monocotyledons, and contain a number of anatomical 

 facts regarding the stem which support the view that 

 the Dicotyledons are the primitive forms, from which 

 the Monocotyledons have been derived. — Miss Maud D. 

 Haviland : The life-history and bionomics of Myzus 

 ribis, Linn, (red-currant Aphis). Among the many 

 facts established it was shown that there are two 

 forms of this species which differ in the minute 

 structure of the antennae and in the dimensions 

 of the abdomen and wings, and are apparently 

 correlated with the nature of the food. The 

 species is migratory, and in summer colonises 

 certain species of labiate and other weeds, but 

 this change of host-plant is not obligatory, and the 

 entire life-cycle may be passed on the red cur- 

 rant. There is a decline in fertility in the later 

 summer, caused probably by lower birth-rate. This 

 may be considered as one of the factors accounting 

 for the frequent disappearance of the species in 

 August and September.— Dr. C. G. Knott : Further 

 note on earthquake waves and the interior of the 

 earth. There was evidence that as the compressional 

 and distortional seismic waves penetrated to greater 

 depths, the distortional wave reached its maximum 

 velocity at a less depth than the compressional wave. 

 In other words, the rigidity showed signs of falling off 

 in value, while the incompressibility continued to 

 increase. The hypothesis ithat the earth consisted of 

 a nucleus of non-rigid, highly compressed material 

 encompassed bv a shell possessing the properties of 

 an elastic solid was found to fit well in with the 

 facts, the radius of the nucleus being assumed to 

 be four-tenths of the radius of the earth. These con- 

 clusions were based on the accurate determinations of 



NO. 2575, VOL. 103] 



the velocities of the seismic waves at various depths, 

 and are in fair agreement with the views formerly 

 advanced by Mr. R. D. Oldham. 



February 3.— Dr. John Home, president, in the 

 chair.— Dr. J, M'L. Thompson : The stelar anatomv 

 of Platyzoma microphyllum, R. Br. The conductive 

 system of the stem of the Australian fern Platyzoma 

 lies between the two extreme types of conductive sys- 

 tems in modern ferns. These are known as the proto- 

 stele, with a solid cylinder, and the solenostele, charac- 

 terised by a pithed tubular cylinder with both outer and 

 inner phloem and with gaps in its wall. In the Platv- 

 zoma there is the pithed cylinder, but no gaps and no 

 inner phloem. In the majority of specimens examined 

 the conductive system was a'n unbroken and unper- 

 forated pithed cylinder, but in the smallest, and 

 apparently youngest, specimen the conductive system 

 was locally g protostele which was directly transformed 

 as the stem was followed forward into the pithed 

 cylinder without gaps in the wall and without inner 

 phloem. The facts were in favour of the view that 

 the stele of Platyzoma is the result of upgrade de- 

 velopment directly from within an original protostele. 

 — Capt. E. W. Shann : The comparative anatomv of 

 the shoulder-girdle iand pectoral fin of fishes. The 

 observations extend over a wide series of fish types, 

 such as Rhina, Callorhynchus, Accipenser, Polypterus, 

 and Zeus. A new nomenclature was introduced based 

 on the divisions of the great lateral muscles which are 

 found to be constant for any particular group of fishes. 

 The primitive nature of the muscle system in 

 Selachians is emphasised. Among the H'olocephali 

 certain characters foreshadow the condition which 

 obtains in the higher vertebrates. — Sir Thos. Muir : 

 Note on the determinant of the primary minors of a 

 special set of (n— i)-by-n arrays. 



Paris. 

 Academy of ' Sciences, February 17. — M. Leon 

 Guignard in the chair. — A. Rateau : The flow of 

 gas at very high pressures. The classical formulae 

 are based on the gas law pv-RT, and these become 

 inexact when p is high, several hundred atmospheres. 

 Formulas based on the characteristic equation 

 p(v-a) = RT are developed. — J. Drach : The integra- 

 tion by quadrature of the equation d^y / dx^ = lf{x) + h]y . 

 — J. Cabannes : The diffusion of light by the molecules 

 of the air. The proportionality predicted by the theory 

 of Lord Rayleigh, bet^^een the luminous intensity 

 diffused laterally by a transparent gas and the number 

 of molecules in the illuminated volume, has been 

 exactly verified by a method of photographic photo- 

 metry devised by MM. Fabry and Buisson. Since 

 certain ultra-violet radiations cause some complica- 

 tions, it is advisable, in the experimental verification, 

 to suppress radiation with a wave-length below o-t,ij.. — ■ 

 P. Braesco : Precipitated amorphous silica. From 

 experiments on the coefficient of expansion it is con- 

 cluded that precipitated silica, dehydrated and heated 

 to 600° C, is really amorphous silica, but if calcined 

 at temperatures above 1000° C. it becomes crystalline 

 in the form of cristobalite. — M. Portevin : The in- 

 fluence of various factors on the critical speed of 

 tempering in carbon steels. — P. Nicolardot and A. 

 Reglade : The estimation of zirconium. In a solution 

 containing 20 per cent, of sulphuric acid zirconium can 

 be quantitatively separated from iron, aluminium, and 

 chromium by ammonium phosphate.^ — G. Delipine : 

 The carboniferous limestone in the Lille district. — A. 

 Vacher : An old direction of the Ranee valley. — G. 

 Reboul and L. Dunoyfcr : A rule for predicting baro- 

 metric variations and its coefficient of certainty. — E. 

 Mathias : Sketch of a theorv of rain. The influence 



