SCIENTIFIC MEMOIRS. 
VOL. IV.—PART XV. 
ARTICLE XII. continued. 
On the Employment of Polarized Light in studying various ques- 
tions of Chemical Mechanics. By M. Bior, 
Section Il.—On the relations which exist between the densities 
of mixed systems, and those of the partial systems which consti- 
tute them at a constant temperature. Agreement of these re- 
lations with the resultants of the action exercised by these 
different systems on polarized light. 
38. WHEN pursuing a path of research so novel and so my- 
sterious as that on which we are now engaged, we must avail our- 
selves of all the aids which may throw any light upon it. With 
this view I shall fortify the deductions drawn above from the 
optical characters, by mentioning a class of facts of a wholly 
different nature which agree with them completely. 
When a constant weight P of an active substance is associated 
with a variable weight E of an inactive liquid, without these two 
bodies decomposing each other, if the mass E is just sufficient, 
or more than sufficient, to saturate completely the affinity of P 
for it, we have established in §§ 14 and 27 that the function 
a(P+E) 
Pls 
stituted with any doses whatever of the liquid E, thus in excess. 
Now, under such circumstances, the chemical groups formed 
by the combination of P and of E being perfect, the quantities 
of E added in excess can no longer modify them. Therefore the 
systems thus saturated should mix with the ulterior portions 
of E without either contraction or dilatation of volume, which 
may be proved by the comparison of their successive densities 
VOL. IV. PART XV, 2c 
must remain constant in all the mixed systems, con- 
