IOWA ACADEMY OP SCIENCE 
135 
both ground and unground portions. The grinding could not be carried on 
in a porcelain mortar on account of the tendency to cling to the sides of the 
dish. The portion for the determination was placed as nearly as possible in the 
center of the crucible, where it fused to a round ball, thus avoiding the tendency 
to creep over the sides. The tests failed to show any decomposition of the salts 
by heating. The water was also determined in an air bath at a temperature of 
from 105 to 110 degrees, but equally good results were attainable in the ordinary 
way. 
Coarse Fine 
(Per cent) (Per cent) 
A 1 NH 4 (S 002 . I 2 H 2 O. 
Unground 47.13 46.98 
Ground 44.60 44.75 
Loss 2.53 
A 1 K(S 04 ) 2 . I2H2O. 
Unground 45.48 
Ground 42.97 
2.23 
45.44 
43.42 
Loss 2.51 2.02 
Strontium Chloride, SrCL. 6 H 2 O. 
Only a small quantity of the water is removed at a low temperature. It 
decomposes more easily than barium chloride, and the heating must be longer 
continued and at a lower temperature. 
Uncrystallized 
Crystallized 
(per cent) Coarse (per cent) Pine (per cent) 
Unground 39.94 40.41 39.63 
Ground 38.92 ' 38.42 38.10 
Loss 1.02 1.99 1.53 
Borax, Na2B407. IOH 2 O. 
This salt is quite efflorescent, and as the specimen at hand had been in contact 
with the atmosphere for some time, no determination was made before crystal- 
lizing. The work was pushed as rapidly as possible before any change in the 
crystals could take place. A part of the loss is undoubtedly due to efflorescence. 
Coarse (per cent) Pine (per cent) 
Unground 42.39 42.15 
Ground 38.66 38.82 
Loss 3.73 3.33 
Disodium Phosphate, Na2HP04. 12 H 2 O. 
This salt was the most difiicult to handle of any of the series. After grinding 
for about an hour, flt became pasty, adhering quite firmly to the sides of the 
agate mortar. If constantly scraped loose, it soon becomes a dry powder again. 
It was difficult to secure uniform results owing, no doubt, to the effect of atmos- 
pheric changes upon the crystals. The results given, which seem somewhat 
erratic and surprisingly high, are considered a fair sample of those obtained. 
