270 REPORT OF THE CHEMIST OF THE 
The curves of Fig. 17 signify that,— 
(1) When an acid or other substance is adsorbed from solution, 
the initial concentration, however small, is always reduced by con- 
tact with the adsorbent. 
(2) The equilibrium concentration varies wih initial concentration 
in each case. There is no equilibrium constant for the concentration. 
- 
Free HC/——> 
2 
FESS 
3 
> 
~2 
aS 
a 
y N 
48 S00 
Se 
of 
iS) TAU 
2 OOO 
° 
— 400 
of 6 8 /0 72 LG IE W208 22 2 2 Ge 30 
Hours Contact———~ 
Fic. 18.— Showing decrease of concentration of free hydrochloric acid 
resulting from action of casein in taking up acid. (Table VIII, column 3.) 
Comparison with Figs. 16 and 17 shows that the curves are characteristic 
of adsorption. 
