198 



M. J. A. Groshans on the 



Table XX. gives the value of v r for some groups of these 

 substances, and also the volumes (constant) of vapour. 



Table XX. 



Name. 



Formula. 



V 



S°, 

 observed. 



Autho- 

 rity. 



v r . 



c. c. of 

 vapour. 



Toluol 



C 7 H 8 

 C 8 H 8 2 

 C 8 H 8 3 



C 4 H 10 O 



C 5 H 10 O 2 



C 7 H ]4 2 

 C 8 H U 4 



119-57 

 15146 

 15723 



105-97 

 140-56 



128-08 



176-53 

 209-71 



108 



199 

 223 



35 

 126 

 100 



143 

 217 



No. 

 Pe. 

 Kp. 



Kp. 



K P . 

 Kp. 



85-7 

 87'7 

 86-5 



93-9 

 96-2 

 937 



115-8 

 116-8 



260 

 255 



258 



238 

 232 

 238 



193 

 191 



Methyl benzoate ... 

 Methyl salicylate . . . 



Ether 



Ethyl carbonate ... 

 Ethyl propionate . . . 



Ethyl valerate 



Ethyl succinate 



No=Noad; Pe=Peligot; Kp^Kopp. 



It is clear that the phenomenon of the constancy of vr 

 points to equality at the same time of the constants Tn/a and 

 v s n/a ; whence it follows that 



v's ~ T'' 



Here is another consequence of the above : — 

 Since it has been shown that the law of density numbers is 

 applicable to the volumes of vapour T and T' of compounds, 

 it must also be applicable to the liquid volumes v s and v f 8 . 



Application of the Neiv Law to Volumes of Liquids at their 



Boiling-points. 

 The properties of the liquid volumes are different from those 

 of the gaseous volumes. These last, when of isomeric bodies, 

 can differ greatly; the former, on the other hand, are equal, 

 or almost exactly so. But it seems to me a little premature 

 to make any extended remarks on the subject of liquid 

 volumes in general. 



If d 8 be the density of any liquid whatever at the boiling- 





point S°, the 



volume v 8 = -7- 

 d s 



and in applying the law to 



these volumes we obtain the constants v s n/a analogous to 

 Tn/a (this constant v s n/a or r 5 B/a is the same as n/d s or 

 B/ds). Instead of writing v 8 n/a, I shall w r rite k s , which is 

 more convenient. The following Table contains three groups, 

 each of three members from Tables XIX. and XX. I have not 

 been able to form larger groups, comprising 8-10 compounds, 

 for the data relating to the volumes of liquids are too scanty. 



