yune 2i, 1^76] 



NATUM 



1S3 



rather than Coniferous affinities. One winged seed alone (Polyp- 

 terospermum), from the uppermost coal-measures at Ardwick, 

 resembles a true conifer. In conclusion, the author calls atten- 

 tion to the number of yet unknown stems and leaves of 

 Phanerogams, which must have belonged to the numerous seeds 

 now known to exist in the coal-measures of England, France, 

 and North America. 



Mathematical Society, June 8.— Prof. H. J. Smith, F.R.S., 

 president, in the chair.— Mr. A. B. Kempe spoke on a general 

 method of describing'plane curves of the «th degree by link-work. 

 He first described what he calls the revtrrsor and the m7tlti- 

 flicaior. (These were first described by him in the " Messenger 

 of Mathematics," vol. iv. pp. 122-3, i" ^ paper " On some New 

 Linkages.") He then explained the additor and the translator. 

 Let <^{x, jj/) = # be the equation to any plane curve of the Mth 

 degree, and let P be any point on the curve ; construct the link- 

 work parallelogram O A PB in which 



OA=BP = a, OB = AP = b, 



and let the angle A o X = 0, and the angle B X — <(>, then — 

 X = a cos + ^ cos (p 

 y = a cos (o - ~\ + d cos (<j> — -\ 



Substitute these values of .r and y in 4>{x,}'), expand and convert 

 powers of cosines into cosines of multiple angles, and ?hen the 

 products of cosines into the cosines of the sums and differences 

 of angles, we shall then get — 



<j>(x,}') = -Z[A ccs{rip ^ SO :k a)]+ C, 



where r, s are positive integers, and a = — or o and A and C 



2 

 are constants. The author then proceeded to show how the 

 constructions could be effected by his link-work, and he pointed 

 out that his method would not be practically useful on account 

 of the complexity of the link-work employed, a necessary conse- 

 quence of the perfect generality of the demonstration. The 

 method has, however, an interest as showing that there is a way 

 of drawing any given case ; and the variety of methods of 

 expressing particular functions that have already been discovered 

 renders it in the highest degree probable that in every case a 

 simple method can be found. There is stil', therefore, a wide 

 field open to the artist to discover the simplest link-woiks that 

 will describe particular curves. Mr. Kempe further poin'ed 

 out that the extension of the demonstration to curves of 

 doable curvature and surfaces clearly involves no difficulty. 

 — Mr. S Roberts then gave an account of a further note on the 

 motion of a plane under certain conditions. (The former paper 

 was read June 8, 1871). — Mr. J. J. Walker communicated a 

 method of reducing the equation of a nodal plane cubic curve to 

 its canonical form, in which the lines of reference are the nodal 

 tangents and axis of inflexion. — Prof. Cayley described a surface 

 connected with the sinusoid. Its edge of regression was given 

 by the equations x = r cos <p, y = r sin </>, and 2= r cos a <p. — The 

 president made a few remarks in connection with a recent note 

 by M. Hermite, on a theorem of Eisenstein's. 



Zoological Society, June 6.— Dr. A. Giinther, F.R.S., 

 vice-president, in the chair. — The Secretary exhibited some 

 specimens of a Land-crab, from Ascension Island (Geocarcinus 

 Ugostoma), which had been presented to the Society by Dr. J. 

 B. Drew, and read a note by Dr. Drew on their habits. — Mr. 

 Sclater exhibited skins of a male and female of the new Phea- 

 sant from Borneo lately described by Mr. Sharpe as Lobiophasis 

 buhoeti. These birds had been obtained alive for the Zoological 

 Society of Amsterdam, but the female only had lived to reach 

 Amsterdam. — A letter was read from Mr. J. H. Gurney, con- 

 taining some notes on the breeding of a pair of the Polish Swan 

 (Cy§:nus immutabilis of Yarrell), and a description of the young 



birds. — A communication was read from Dr. Julius von Ilaast, 

 F.R.S., containing some note? on the skeleton of Ziphius Novce 

 Zealandice. — A second communication from Dr. Julius von 

 Haast, F.R.S., contained some notes on Meseplodon flmveri.^ — 

 A communication was read from Dr. G. E. Dobson, containing 

 a description of certain peculiarities in the structure of Mysta- 

 cina tuberculata, which induced him to believe that this Bat 

 used its feet for purposes of locomotion on branches and leaves 

 of trees. — Mr. A. H. Garrod read the first part of a memoir on 

 certain anatomical characters which bear upon the major divisions 

 of the Passerine Birds. — A communication was read from Mr. 

 E. L. Layard, C.M.G., containing notes on the Birds of the 

 Navigators and Friendly Islands, with some additions to the 

 ornithology of Fiji. — Mr. H. Adams and Mr. G. French- Angas 

 communicated descriptions of five new species of Land Shells 

 from Madagascar, New Guinea, Central Australia, and the 

 Solomon Islands. 



Royal Microscopical Society, June 7. — Mr. H. J. Slack 

 in the chair. — A number of presents to the society were 

 announced, including some rich diatomaceous earth from Santa 

 Monica, near Los Angelos, sent by Mr. Hanks, of San Fran- 

 cisco. — A paper on a photograph of Nobert's bands, by Count 

 Castracane, was read to the meeting and was supplemented by a 

 short communication upon the same by Mr. II. C. Sorby. — Mr. 

 Henry Davis gave an interesting account of some new observa- 

 tions which he had made upon Chonochilt(s volvox, and illus- 

 trated his remarks by drawings showing the principal features of 

 the genus as distinguished from the Melicertians. — Mr. Chas. 

 Stewart described and exhibited under microscopes in the room 

 some minute seines found only round the pentagonal opening on 

 the under side of the shell of the Echinoderms ; he also gave a 

 description of the remarkable structure of the large lachrymal 

 gland of the common turtle, and exhibited preparations. 



Victoria Institute, May 29. — Annual Meeting. — The Ri»ht 

 Hon. the Earl of Shaftesbury, K.G., in the chair. The address 

 was delivered by the Rev. Prof. Birks, of Cambridge. 115 

 meTibers and associates have joined during the year, and the total 

 number has risen to 690, two-thirds of whom are country and 

 foreign members. The president, on behalf of the Institute, 

 presented a testimonial to Capt. F. Petrie, who had acted as 

 honorary secretary and editor of the " Transactions " for the last 

 five years and a half. 



Berlin 



German Chemical Society, May 22. — C. Scheibler, vice- 

 president, in the chair. — A. Fi-cher described a modified water 

 air-pump, remarkable for its cheapness. The brass instrument 

 is sold by Messrs. Dreyer and Rosenkranz in Hanover for ten 

 shillings, or wiih a manometer fixed to it for twenty shillings. Ic 

 can be fixed to any laboratory table. — A. Horstmann confirmed 

 observations by F. Isambert respecting the dissociation of the 

 combination of ammonia with chloride of silver. For every 

 degree of temperature a certain pressure can be observed, at 

 which the separated bodies do not le-combiue and the combina- 

 tion ceases to be decomposed. He also observed the existence of 

 two compounds of the formulas AgCl. 3NH3 and 2AgCl. 3NH3. 

 — A. Steiner has obtained the following combination of sul- 

 phuretted hydrogen with fulminic acid by passing HjS into 

 fulminate of mercury — 



CjHjNaOj + HgS = C(N02)H2 - CS. NII2, 

 microscopical crj'stals, yielding, with a surplus of sulphuretted 

 hydrogen, oxalic acid, sulphocyanide of ammonium, and 

 sulphur — 



2(C2H4N202S) + H^S = 2CN2H,S + C3H2O4 -f S. 



The same chemist by treating fulminurate of ammonium with 

 sulphuiic acid has obtained nitro-acetonitrile, CH2NO2 . CN 

 (hitherto unknown), beautiful colourless crystals, fusing at 40", 

 burning with a brilliant flame. The substance is not identical 

 with fulminic acid, because with mercury and silver it forms 

 monobasic and not dibasic salts. He also described two 

 bodies formed by the reaction of ammonia on fulminate 01 

 mercury, of the formulae CgHuNgOj and CyHjjNuOs, guani- 

 dines, containing fulmi-guanurates. At the end, double 

 salts of fulminate of mercury with sulphocyanide of potassium 

 and ammonium, and also with cyanide of potassium were 

 described. — E. Demole published researches on a body lately 

 described by Baumstark, C4HglO, under the name of ethylidene- 

 iodo-oxethyl. Mr. Deinole's researches lead him to suppose that 

 this body is derived from ethylene and not from ethylidene. — A. 



