March i6, 1876 J 



NA TURE 



399 



It appeared to the author of interest to determine (i) if the 

 specific volumes of these liquids exhibit a relation similar to that 

 which is shown by their molecular weights ; and (2) if the relation 

 in their specific volumes is preserved in analogous combinations 

 of the two bodies. He has accordingly determined the specific 

 gravities, boiling-points, and rates of expansion of bromine and 

 iodine monochloride, and of the compounds which these sub- 

 stances form by their union with ethene, CjH^. The observa- 

 tions also serve to determine if bromine and iodine monochloride 

 preserve, when in combination, the volumes which they possess 

 in the free state. 



It is evident from the observations that the specific volumes 

 of bromine and iodine chloride are not equal, neither are the 

 specific volumes of ethene bromide and ethene chloriodide ; the 

 bodies with the greater molecular weights have the greater specific 



volumes. 



Molecular weight. Specific volume. 



Bromine IS9'90 53'62 



Iodine chloride 162-31 56-32 



Ethene bromide 187-90 97'30 



Ethene chloriodide 190-31 ioi"27 



The number obtained for iodine monochloride differs consider- 

 ably fi-om the volume calculated by means of Kopp's values 

 (CI — 228, I = 37-5), viz., 603. The specific volume of bromine 

 (Brj) is also less than Kopp's number, 55-6. The value assigned 

 to chlorine is unquestionably far more accurate than that given 

 to iodine, since the value of the latter element was calculated 

 firom only two or three compounds, whereas the former number 

 was deduced from a comparatively large number of chlorinated 

 products. That the value for iodine needs revision seems to be 

 confimr.ed by Billet's observations of the specific gravities of 

 liquid iodine at various temperatiures. If his resxdts be plotted 

 down and the curve prolonged to the boiling-point of iodine, we 

 find that the specific gravity of iodine at this point is 3780; 

 hence the specific volume of iodine (I.) — 



= i55i5 = 33-5. 



3-780 



If now this value be added to that of chlorine as given by 

 Kopp, we get a result identical, with the observed volume^ of 

 iodine monochloride — 



33-5 + 22-8 = 56-3. 



If we subtract the specific volim:ies of Cj H^ as calculated by 

 the aid of Kopp's values (C = 11, H = 5-5, C3H4 = 44), from 

 the specific volumes of ethene bromide and ethene chloriodide, 

 we obtain numbers which are nearly equal to the specific volumes 

 of bromine and iodine chloride respectively — 



97*30 - 44 = 53 '30. 

 101-27-44= 57-27. 



This correspondence between the two sets of values seems to 

 warrant the conclusion that bromine and iodine chloride possess 

 the same volume in a compound which they have when in the 

 fi-ee state. 



It is not imreasonable to suppose that the same may be true of 

 ethene itself, viz., that at its boiling-point it would possess the 

 same volume which it has in the bromide and chloriodide at 

 their respective boiling-points. On this assumption the specific 

 gravity of liquid ethene would be — 



Calculated from CH^Br, 0-641 



,, CjHJCl 0-624 



Chemical Society, March 2. — Prof. Abel, F.R.S., presi- 

 dent, in the chair. — This meeting was entirely occupied with the 

 discussion of the various points in coimection with water 

 analyses, raised by Dr. Frankland's lecture at the previous 

 meeting. The debate, which lasted imtil a late hour, turned 

 chiefly on the respective merits of Frankland and Armstrong's 

 " combustion method," and of the "albumenoid ammonia pro- 

 cess " of Wanklyn, Chapman, and Smith, for determining the 

 amount of impurity in potable waters. 



Mathematical Society, March 9. — Wm. Spottiswoode, 

 F.R.S., vice-president, in the chair. — Messrs. Cockshott and 

 R. T. Wright were elected members, and Messrs. Elliott, 

 Leudesdorf, and Russell admitted into the Society. — Prof. 

 Cayley made communications on the bicursal sextic and on the 

 problem of three-bar motion. The discovery by Mr. Samuel 

 Roberts of the triple generation of a three-bar curve throws a 

 new Ught on the whole theory, and is a copious source of fiirther 

 developments. Prof. Cayley gives in its most simple form the 



theorem of the triple generation ; he also establishes the rela- 

 tion between the nodes and the foci, and further gives other 

 researches. The two papers are intimately related to one 

 another. — Prof. Clifford spoke on the classification of geometric 

 algebras. He sketched out what had been done by Argand 

 (1806); Mobius (1827); Peacock and the Cambridge School 

 {1834) ; Hamilton (1843) ; Grassmann (1844, 1862) ; Peirce 

 (1870) ; and mentioned results he has himself obtained, for some 

 of which he had not yet got satisfactory explanations. 



Zoological Society, March 7. — Dr. A. Gunther, F.R.S., 

 vice-president, in the chair. — Dr. Giinther exhibited and made re- 

 remarks on specimens of a minute Australian mammal (Antechitius 

 minutissimus) and of a species of Palythoa parasitic on a Mediter- 

 ranean sponge. — Prof. Garrod read a paper on the anatomy of the 

 Courlan (Aramus scolopaceus), which he regarded as showing in 

 many respects a close affinity to the Cranes {Grus). — A com- 

 munication was read from Mr. T. E. Buckley, containing 

 remarks on the past and present geographical distribution of the 

 larger mammals of South Africa. — Dr. Cobbold, F.R.S., read 

 the fourth of his series of notes on Entozoa. — Sir Victor Brooke, 

 Bart., read some supplementary remarks on the newly discovered 

 Persian Deer i^Cervus mesopotamicus), based on additional speci- 

 mens and information received firom Mr. Robertson, H. B.M. 

 Vice-Consul at Busreh. — A second communication from Sir 

 Victor Brooke contained further observations on Schomburgk's 

 Deer {Cenms schomburgki) of Siam. 



Royal Microscopical Society, March i. — Mr. H. C. Sorby, 

 F.R.S., president, in the chair. — A paper was read by Mr. W. 

 Hartley, F.C.S., descriptive of certain observations and experi- 

 ments on the fluids contained in quartz cavities, and which ap- 

 peared to be liquid carbonic acid, mixed in most cases with 

 water. The subject was illustrated by drawings and by speci- 

 mens, and experimental demonstrations under the microscope. — 

 A paper was also read by Mr. F. Rutley on the structure of cer- 

 tain rocks. Obsidian and Leucite, and on the spheroidal structure 

 observed in the perlites. The subject was freely illustrated by 

 diagrams and specimens exhibited in the room. A paper by the 

 Rev. W. H. Dallinger, on a new arrangement for illuminating 

 and centering for high powers, was taken as read, it being under- 

 stood that though of great interest it could not readily be ex- 

 plained without the numerous illustrations by which it was 

 accompanied. 



Institution of Civil Engineers, Feb. 22. — Mr. G. R. 



Stephenson, president, in the chair. The paper read was on 

 the Probable Errors of Levelling, with Rules for the Treatment 

 of Accumulated Errors," by Mr. Wilfred Airy, B.A. 



Feb. 29. —Mr. Geo. Robt. Stephenson, president, in the chair. 

 — The first paper read was on the floods in England and Wales 

 during 1875, and on water economy, by Mr. George James 

 Symons, secretary to the Meteorological Society. — The second 

 paper read was on evaporation and on percolation, by Mr. Charles 

 Greaves. 



Victoria (Philosophical) Institute, March 6. — A paper on 

 the Horus myth in its relation to Christianity, was read by Mr. 

 W. R. Cooper, F.R.A.S. 



Manchester 



Literary and Philosophical Society, Dec. 6, 1875. — Mr. C. 

 Bailey, vice-president, in the chair. — Mr, Sidebotham, F.R.A.S., 

 sent for exhibition some sand from a river far inland of New 

 Guinea, containing particles of gold, magnetic and non-magnetic 

 iron, foraminiferK, silicified fragments of echini, and shells. — Mr. 

 ' J. Cosmo Melvill exhibited two specimens of the Spurge Hawk 

 ': Moth {Dnlephila euphorbia), said to have been captured in the 

 • larval state at Ecclesboume, near Hastings, feeding in all proba- 

 bihty on Euphorbia amygdaloides, as he subsequently visited the 

 spot and could see no trace of any other Spurge. 

 I Jan. 17. — Mr. John Barrow in the chair. — Mr. Sidebotham, 

 F.R.A.S., exhibited a magnified drawing and specimens of 

 ' Lymexylon navale firom Dunham Park, and read a short paper on 

 \ the life history of the insect, which he and Mr. Chappell had 

 studied since its discovery in Dunham Park in 1872. Mr. Side- 

 botham also read a paper on Psammodius sulci^oUis, and exhi- 

 bited specimens taken at Southport in 1875. — Mr. Plant exhibited 

 various objects of interest, including a Longicom Beetle {AstinO' 

 mus adilis) from a coal mine near Manchester ; also cases of a 

 North American Caddis Worm (Phrygaiiea sp.) much resembling 

 a mollusc of the genus Valvata, and once named by Lea Valvata 

 arenicoia. 



