Gooch and Fuirbanks—Halogens in Mixed Silwer Salts. 31 
AgCltaken. AgBrtaken. Agealculated. Ag found. Error. 
grm. grm. grm. erm. grm. 
1°0608 ee 0°7985 0°7990 0°0005 + 
1°4380 Bape 1°0823 1°08238 0°0000 
0°9998 ee 0°7525 0°7522 0°0003 — 
— 0°9959 0'5721 0°5723 0°0002 + 
Bhd 42 09979 0°5731 0°5732 0°0001 + 
1:0044 0°4988 1°0426 1°0422 0°0004— 
0°4933 0°4966 0°6559 0'6568 0°0009 + 
The manipulation of the method is very easy, and the results 
show that it is capable of yielding accurate results. The 
current ranged from 0°5 to 0°25 amperes, and for convenience 
the process was continued over night though the reduction of 
amounts such as we treated is usually complete in six or seven 
hours. 
Unfortunately this process which works so well with the 
mixture of chloride and bromide is not applicable to the 
reduction of silver iodide or to mixtures containing it. Experi- 
ment proved that the iodine set free in the electrolysis works 
over and over again upon the spongy silver constantly regener- 
ating silver iodide to a greater or less degree. As the result of 
many attempts to destroy the liberated iodine without intro- 
ducing anything objectionable into the solution we finally 
settled upon a mixture made by neutralizing two parts by 
volume of ordinary (40 per cent) acetic acid with ammonia, 
adding one part of ammonia, one part of alcohol, and one 
part of aldelyde (75 per cent). Such a solution we found to 
work very well on the whole, but as the reduction progresses 
it frequently happens that a deposit of white ammonium iodate © 
forms upon the anode, which introduces too great resistance to 
the current. This deposit of iodate is, however, easily removed 
from the electrode by dipping it into hot water. Whenever 
the solution isso exhausted that free iodine begins to appear 
the liquid should be carefully decanted and replaced by fresh; 
and before the operation is ended the decanted solutions and 
the washings of the electrode should be filtered through the 
crucible, and the residue submitted again to the action of the 
current, to make it certain that loosened particles of silver or 
silver salt possibly poured off or removed on the electrode 
shall not be lost finally. The necessity of keeping the process 
under occasional supervision renders it undesirable to continue 
the action over night. In some eases of prolonged action 
without attention we have noticed the formation of gummy ear- 
bonaceous matter which could not be subsequently removed 
without the application of a degree of heat which might 
endanger the platinum in contact with the reduced silver. 
