358 



NATURE 



[January 20, 1910 



year (Phil. Trans., Series A, vol. ccix., pp. 379-4'3. >909). 

 and, in addition, to a series of measurements of the elec- 

 tricity of snow made during the winter 1908-9. All the 

 main conclusions drawn from the previous work have been 

 confirmed, and it may now be stated with confidence that 

 in Simla (a) more than three times as much positive as 

 negative electricity is brought down by the rain ; (b) the 

 heavier the rainfall, the more likely is it to be positively 

 charged ; (c) light rain is, as a rule, more highly charged 

 than heavy rain, irrespective of whether the charge is 

 positive or negative. With regard to the electrification of 

 snow, the measurements indicate that in Simla iS) the 

 positive charge carried down by the snow is between three 

 and four times as great as the negative charge ; (<?) snow 

 is generally more highly charged than rain. — L. Vegfard : 

 The polarisation of X-rays compared with their power 

 of exciting high-velocity kathode rays. 



Mathematical Society, January 13. — Sir W. D. Niven, 

 president, in the chair. — Dr. H. F. Baker: (i) The theory 

 of the cubic surface ; (2) an example of the expansion of 

 a function in a series of polynomials. — G. N. Watson ; 

 The harmonic functions associated with the parabolic 

 cylinder. — Dr. H. de S. Pittard : Note on the theory of 

 sets in probabilities.- — H. Bateman : The transformations 

 of coordinates which can be used to transform one physical 

 problem into another. — G. H. Hardy : Note on a former 

 paper on the theory of divergent series. — Dr. VV. H. 

 Young; : Homogeneous oscillation of successions of func- 

 tions. — Dr. W. H. Young and Mrs. G. C. Young : The 

 determination of a semi-conlinuous function from a count- 

 able set of values. — J. E. Campbell : Cyclic congruences. 



Royal Astronomical Sncjety, January 14. — Sir Dnvicl 

 Gill, K.C.B., president, in the chair. — J. Evershed ; 

 Radial movement in sun-spots : second paper. The paper 

 contained further investigations on the spectra of sun- 

 spots, made at the Kodaikdnal Observatory, India. The 

 spectra of every considerable spot had been photographed, 

 and it was invariably found that, except when the spot 

 was near the centre of the disc, the lines crossing the spot 

 were inclined towards the red on the side nearest the 

 limb, and towards the violet on the side nearest the centre 

 of the disc. Assuming this inclination to be duo to motion 

 in the line of sight, the conclusion seemed inevitable that 

 spots are centres of a force directed outwards in a hori- 

 zontal plane. This would explain the motion of recession 

 on the side nearest the limb, and of approach on the side 

 nearest the centre of the disc. The effect would not be 

 observed in the case of a spot near the central meridian, 

 where there would be no motion in the line of sight. A 

 study of the calcium lines showed a motion in the opposite 

 direction (towards the centre of the spot), indicating an 

 in-draught of calcium vapour in the higher chromosphere. 

 No evidence was obtained of an upward current over spots, 

 but there were some indications of downward movements. 

 There are also indications of cyclonic motion, but in the 

 opposite direction to that shown in some of Prof. Hale's 

 spectroheliographs. — .\. C. D. Crommelin : Diagram 

 illustrating a method of charting the geocentric places of 

 a comet referred to a fixed radius vector. — R. W. Wood : 

 The moon in ultra-violet light ; spectro-selenography. The 

 author recommended a spectroscopic method of investi- 

 gating the nature of the surface of the moon. 



Institute of Metals, January 18.— Sir William H. 

 White, K.C.B., F.R.S., president, in the chair.— G. D. 

 Bengrough and B. P. Hill : The properties and constitu- 

 tion of copper-arsenic alloys. One of the principal objects 

 of the paper was to bring forward data for an authori- 

 tative pronouncement upon the best proportion of arsenic 

 to be used to secure copper alloys having greater strength 

 and rigidity, and greater resistance to the corrosive action 

 of gases at high temperatures, than commercially pure 

 copper. The first portion of the paper dealt with the 

 mechanical properties of the alloys of industrial import- 

 ance, and the second with their chemical composition. In 

 the latter section the authors denied the existence of the 

 compound Cu'As, proposed by Hiorns, and confirmed the 

 existence of the compounds Cu,As and CUjAs,, already 

 proposed by Friedrich. — E. A. Smith : The assay of in- 

 dustrial gold alloys. The author gave a brief comparative 

 description of the methods in general use for the assay 

 NO. 2099, VOL. 82] 



of industrial gold alloys, based on experimental work 

 carried out at the Royal School of Mines and in the 

 University of Sheffield. It was shown that the results for 

 gold assay were invariably higher when determined by 

 direct cupellation with parting silver than when determined 

 indirectly by double cupellation. — Dr. R. Seligman and 

 F. J. Willo'tt : The analysis of aluminium and its alloys. 

 A detailed description was given of the technical methods 

 of estimating the various foreign elements (copper, zinc, 

 nickel, magnesium, tin, lead, manganese, titanium) and 

 impurities (silicon, iron, and sodium) to be found in com- 

 mercial aluminium and aluminium alloys. It was pointed 

 out that the effect of these elements, particularly in minute 

 proportions, upon aluminium was but little understood, 

 and that it was desirable that research be directed along 

 those lines. 



Edinburgh. 

 Royal Society, December 20. 1909. — Sir William Turner, 

 K.C.B., president, in the chair. — Sir William Tumor: 

 'I'he aborigines of Tasmania, part ii., the skeleton. The 

 paper gave further particulars as to the specimens of 

 Tasmanian skulls and skeletons now extant, and described 

 in detail the bone anatomy of the specimen in the museum 

 at Brussels. The discussion emphasised the fact that the 

 Tasmanian had differed in important particulars from the 

 ordinary black races, but resembled them in other respects. 

 As regards the flattened femurs, the Tasmanian suggested 

 afilnity with the cave-dwellers and the Maoris, whereas in 

 the form of the pelvis there was greater resemblance to 

 the European races. — W. T. Gordon : The structure and 

 affinities of Zygoptcris Romeri (Solms). The petiole of 

 this form was described by Solms Laubach from the Culm 

 of Falkenberg. A few years later a similar petiole was 

 obtained by Renault from rocks in Autun, and called 

 Diplolabis Esnostcnsis. The present specimens of stems, 

 petioles, and roots were found last year by the author in 

 rocks of Calciferous Sandstone age at Pettycur, in Fife. 

 The stem is protostelic, and is circular in transverse 

 section. The wood consists of an inner zone with short 

 elements, and an outer zone with longer tracheides. All 

 the wood elements, whether long or short, have reticulate 

 thickenings in their walls. The stem branches dicho- 

 tomously. Appendages are given off from the stem at long 

 intervals. These are either petioles or roots. At successive 

 levels in the petiole the trace is indistinguishable from the 

 characteristic trace in several different genera. Zygopteris 

 Romeri is thus a synthetic type so far as the stages in 

 the development of its petiole are concerned, and in the 

 possession of a protostele the plant is the most primitive 

 zvgopterid yet discovered. In its organisation it has an 

 important bearing on the origin of the Botryopterida; and 

 the Osmundacp.-c. — Prof. Gwynne Vaughan and Dr. R. 

 Kidston, F.R.S. : The fossil Osmundacca?, part iv., and 

 conclusion. Two new species are described, Osmundite 

 Kolbei and O. Schemnlciensis. The latter is closely 

 similar to the modern Osmunda, but the anatomy of the 

 former is described for the first time. It is very interest- 

 ing owing to the position it takes up between the 

 Osmundacere that have a solid xylemed stele and those 

 with a broken ring of xylem surrounding a pith. The 

 xylem is broken up into separate strands, but its pith con- 

 tains scattered groups of tracheal elements. The general 

 results of the whole paper are summed up, and the relation- 

 ships between the Osmundaces and the Zygopteride.'B are 

 discussed in some detail, especially with reference to the 

 peculiarities of the structure of the zygopterid leaf-trace. — ■ 

 Prof. J. C. Ewart, F.R.S. : The restoration of an ancient 

 race of horse. .^bout the middle of last century Owen 

 received two upper molar teeth of a small member of the 

 Fquid^E familv from a cavernous fissure at Oreston, near 

 Plymouth. Similar teeth were obtained from the drift 

 lying over the London at Chatham and from Kesingland, 

 in Suffolk. Owen realised that these molars could not 

 belong to a small variety of Equiis fnssilis — the species 

 now represented bv the wild horse IE. przcwalsldi) of 

 Mongolia — but he had some difTiculty in deciding whether 

 they were the teeth of a small r.nce of horses or the teeth 

 of an ass or a zebra. Eventually he concluded that the 

 Oreston teeth belonged to a " wild ass or quagga." which, 

 with a wild horse and a wild boar, entered " into the 

 series of British Pliocene hoofed mammals." To this 



