14G 
IOWA ACADEMY OF SCIENCE 
cold water much longer than any of these^ in neither case had it wholly 
disintegregated, though it was much reduced in size. 
In order to ascertain the exact nature of those quantities given in the 
foregoing tables under the head ''Insoluble,” a number of these pre- 
cipitates were fused in a platinum crucible with Na-CO^. The results 
of the analyses which were made follovdng the fusion are showm in Table 
V. These analyses showed a very large per cent as still insoluble. To 
assure myself fully that this part was SiO^, I placed several of these 
l^reeipitates in platinum crucibles and moistened with sulphuric acid 
and then hydrofluoric acid was added and the whole volatilized. This 
process left only a slight discoloration on the platinum. Suspecting 
that this was largely iron, I tested it with pota'ssium ferro-cyanide and 
obtained the blue color which this gives with iron. The per cent given 
as SiO', while it is practically all this, really includes, therefore, a 
small trace of iron. 
TABLE I (Normal). 
NO. 1: TEMPERATURE OF WATER, 98° C. 
First 1 
Running 
Second 
Running 
Thn-d 
Running 
Fourth 
Running 
Fifth 
Running 
Weight of piece 
7.1120 
6,3376 
5.8701 
5.5690 
5.1410 
Insoluble 
.2428 
.2086 
.1795 
.1857 
.1880 
ALOg and Fe-Og 
.0617 
.0427 
.1040 
.0353 
.0224 
Ca CO 3 
.4655 
.2148 
.0044 
.2014 
.1412 
MgCOg 
.0044 
.0014 
.0132 
.0056 
.0059 
Per cent dissolved 
10.89 
7.38 
5.13 
7.69 
6.95 
Total per cent dissolved., 
10.89 
17.46 
21.69 
27.71 
32.74 
Time run 
120 hrs. 
120 hrs. 
120 hrs. 
120 hrs. 
120 hrs. 
Total time 
120 hrs. 
240 hrs. 
360 hrs. 
480 hrs. 
600 hrs. 
TABLE II (Normal). 
NO. 1: TEMPERATURE OP WATER, 17° C. 
First 
Running 
Second 
Running 
Third 
Running 
Fourth 
Running 
Fifth 
Running 
Weight of piece | 
6.8130 
6,2704 
5.7063 
5.2784 
4.8122 
Insoluble - 
-.3555 
.3960 
.3040 
.3335 
.3460 
AI 2 O 3 and PeoOg 
.0406 
.0203 
.0435 
.0260 
.0182 
Ca CO 3 
.1416 
.1446 
.0787 ■ 
.1038 
.1184 
MgCOg 
.0048- 
.0032 
.0017 
.0029 
.0034 
Per cent dissolved .1 
7.96 
8.99 
7.50 
8.83 
10.10 
Total per cent dissolved . . 
7.96 
16.24 
22.52 
29.37 
36.50 
Time run 
120 lu*s. 1 
120 hrs. 
120 hrs. 
120 hrs. 
120 hrs. 
Total time i 
120 hrs. 1 
240 hrs. 
360 hrs. 
480 hrs. 
600 hrs. 
