498 
IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
Concentration 
5 Per Cent 
CuCl 2 
NH 4 C1 
Temperature 
63°C 
Test No. 1 
.16231 
.35727 
Duration of Test 
2% Hours 
Test No. 2 
.15929 
.34984 
With the rise of temperature it is noticed that the two salts 
are approaching’ a different ratio and that the ammonium chlor- 
ide has taken another marked increase. Instead of the ratio of 
1 to 1.25 we have the ratio of 1 to 2.25. 
Concentration 
5 Per Cent 
CuCl 2 
NH 4 C1 
Temperature 
63°C 
Test No. 1 
.07259 
.20596 
Duration of Test 
1 Hour 
Test No. 2 
.08508 
.20188 
This test serves to verify the statement made above concern- 
ing the rapid diffusion of the ammonium salt during the first 
part of the tests. We have in these data more evidence to prove 
that the decrease of the ammonium chloride is more rapid than 
the decrease of the copper chloride, for each additional time 
unit. The ratio between the two salts for the shorter periods 
is higher than for the longer periods. 
Concentration 
5 Per Cent 
CuCl 2 
NH 4 C1 
Temperature 
Room Temp. 
Test No. 1 
.24141 
.53293 
Duration of Test 
10 Hours 
Test No. 2 
.26204 
.51076 
THE DOUBLE SULPHATE OF IRON AND AMMONIUM. 
FeNH 4 (SG 4 ) 2 . 
Concentration 
5 Per Cent 
FeS0 4 
(NH 4 ) ; S0 4 
Temperature 
Room Temp. 
Test No. 1 
.01039 
.03608 
Duration of Test 
2 Hours 
Test No. 2 
.01249 
.04312 
From the above formula we computed the ratio of the two 
constituent salts and found that they were present in the ratio 
of 100 of the iron to 33 of the ammonium sulphate. If then the 
salt does not dissociate we would expect to find three times the 
weight of the iron sulphate as of the ammonium sulphate, in 
the diffusate. But from the above data it is evident that the 
ammonium is much in excess and that the double sulphate dis- 
sociates when in a water solution. 
