132 KEPOBT— 1886. 



151'2°. In this paper the authors confirm the results of Dewar with 

 regard to the Talues of T/P, which is 3"5 approximately for hydric chlo- 

 ride water, ammonia, and marsh-gas, and is greater than this for the 

 more complex molecules derived from these as types. In the order in 

 which the bodies have been named these numbers are given as 3'4, 5' 7, 

 8-4, 3'6, 6-9, 7-9, 10-5. 



In another paper ' the same authors add critical temperatures and pres- 

 sures and values of T/P for other substances ; thus for propyl chloride 

 T/P is 10, for ethylamine GS, for diethylamine 12"2, for triethylamine 

 17'4, for propylamine 9"8, and for dipropylamine 17'7. 



Dilatations and Vapour-densities of Bodies in the State of Gas at High 

 Temperatures — Experiments by V. Meyer, Crafts and Meier, and others. 



The greater part of the determinations of vapour- densities of bodies 

 whose vapour-densities had not been known or were doubtful up to the 

 last ten years has been effected by Victor Meyer alone, or in conjunction 

 with others ; some by Crafts and Meier.^ 



After describing his apparatus as ordinarily used, V. Meyer gives 

 results with CHCI3, CS2, H2O, CcH4(CH3)2, CgH^Br, CfiH^NHa, 

 cymene, CsHsOH, those having the highest boiling-point being heated in 

 the vapour of boiling ethyl benzoate, the vapour-densities in all the cases 

 taken agreeing fairly with the theoretical results calculated fi-om Gay- 

 Lussac's or Avogadro's law — quite nearly enough for practical purposes — 

 thus: 



For CS, For H.,0 



Observed Calculated Observed Calculated 



2-87 2-91 2-292 2-63 -69 -60 -02 -62 



V. Meyer points out that in calculating the observed densities from 

 the direct datum of each experiment the temperature of the bath does 

 not require to be known, but must be quite constant during each 

 determination. 



By improving his process he shows how to get much more accurate 

 results, thus : 



For Water For CSj For Iodine 



Found Calculated found Calculated Found Calculated 



Density '64 '62 2-68 262 8-83 878 



and so for, besides those already mentioned, naphthalene, benzoic acid ; 

 some in a lead-bath, e.g., diphenylamine, mercury, anthracene, anthra- 

 quinone, chrysene, sulphur; and, in a bath of Wood's metal, perchlor- 

 diphenyl. 



For indium chloride the formula InClj corresponded to the found 

 vapour-density, whereas the vapour-densities found by Deville and 



' Ibid. ciii. 6. 



- References; Berichte der Detttschen Chemischen G. 1878, 11. 2, pp. 1868, 2258 ; 

 1879, 12. 1, pp. 613, 1113, 1195, 1282 ; 12. 2. p. U28 (V. and C. Meyer) ; 1880, 13. 1. 

 pp. 423, 776, 851, 1018, 1033 (Crafts and Meier); pp. 391, 394, 401, 407; pp. 399, 

 404, 811 (V. Meyer and Ziiblin) ; pp. 1010, 1013, 1721, 2019 ; 1881, ibid. 14b, p. 1453 ; 

 1882, ibid. 15b, p. 2769; 1883, ibid. 16a, p. 457 (Crafts); 1884, ibid. 17a, 1334; 

 1885, ibid. 18 Ref. p. 133 (C. Langer and V. Meyer) ; a, p. 1501. 



And Pf/rochemische Untersuchungen, von Carl Langer und Victor Meyer. Bruns- 

 wick, 1885. 



