186 
IOWA ACADEMY OF SCIENCES. 
position of the thiosulphate. This is noticeable at as low a 
temperature as 25°, and at 50° becomes very marked, which 
probably accounts for the failure of this point in the dia- 
gram to fall upon the straight line. Above 50° the decom- 
position is too great to permit the further determination of 
solubilities. That light does not affect the solubility of 
the Agl was shown by using, in two experiments, Agl 
made by red light, the agitation being carried out under 
the same condition. 
A few experiments were tried to determine the effect of 
temperature on the solubility of Ag Br in thiosulphate 
solutions, and it was found that as much Ag Br was dis- 
solved at 20° as at 85°. Thus it is seen that the solubility 
of the bromide does not increase with the temperature as 
is so markedly true in the case of the iodide. Cohen states, 
in the case of the chloride that the full amount of Ag Cl 
will be found in solution only when an excess of the Ag Cl is 
avoided and there is just enough present to satisfy the 
equation. 
8Na 3 S 2 0 3 + 2AgCl = (AgSo0 3 Na) 2 Na 2 S 2 0 3 + 2NaCl. 
This method was tried with both the Agl and Ag Br, the 
agitation being continued for several hours, but in neither 
case was as much silver found in the solution as when the 
