Law of Density- Numbers. 



203 





Table XXIII. 







Formula. 



S°obs. 



B. 



dt. 



t°. 



h. 



C 6 H l6 As 



140 



29 



1151 



16-7 (1) 



25-20 



C 6 H l5 Sb 



1585 



34 



1-3244 



15 (1) 



2567 



C b H 15 3 As... 



167 



32 



1-224 



(2) 



2614 



OeHjA^ - 



191 



27 



1075 



(3) 



25-12 



C 6 H 15 4 3? ... 



215 



28 



1086 



(4) 



25-78 



C 6 H 15 4 As... 



236 



33 



1-3264 



(2) 



24-88 



(1) Landolt; (2) Crafts ; (3) Williamson; (4) de Clermont. 



selves in the contrary order to that of the points of ebul- 

 lition S°. 



I have thought it interesting to compare with the above six 

 compounds another, the formula of which resembles those of 

 the bodies in the table: this is ((C 2 H 5 ) 3 Sn)2. Its properties 

 are as follows : — 



S°obs. 



B. 



C^HgoSng 



237° (Ca.) 70 1-4115 (La.) 



K 



49-59. 



Ca=Cahours; La = Ladenberg, who has found S = 267 c 

 We have thus for 



Ci2H 30 Sn 2 . 



. . A = 2x 24-79, 

 C 6 H 15 4 As . . i = 24-88, 



A most complete agreement. 



The value of k t for liquids appears to depend on the value 

 of p and q in the general formula O^H^O,., for, as seen 

 above, the atoms of O, S, and of metals, appear to exercise no 

 influence. With regard to CI, Br, I, they play the part of so 

 many atoms of hydrogen: for instance, the three following 

 metallic ethers should be considered to contain 16 atoms of 

 hydrogen and not 15, for the constants k t are a little higher 

 than those of the compounds of As, P, &c. ; given above. 



Formula. 

 C 6 H 15 ClSn... 



S°obs. 

 . 209 



C 6 H 15 BrSn 223 



C 6 H ]5 ISn 235 



d t . 

 1-428 



1-630 



1-833 



8 



? 



22 



B. 



39 



44 

 49 



Kt. 



2732 



26-98 

 26-74 



These are the experiments of Cahours. 



I regret that space does not allow of my treating of cor- 

 responding temperatures and of the relative expansion of 

 liquids, or of the application of this new Law to solutions. 



