COLONEL P, TOEKE’S EESEAECHES ON SILICA. 
637 
bonate of lithia, differs from that obtained with the carbonates of the other two fhsed 
alkalies, and agrees with the formula SiO. 
These unexpected results suggested to me two lines of research, by following which I 
hoped that some light might be thrown on the apparent anomaly involved in them. 
The first was to determine whether any other acid than the silicic yielded results similar 
to those akeady obtained with carbonates of potash and soda ; and the second was to 
ascertain whether the equivalent of silicic acid could be obtained by means of any other 
volatile acid than the carbonic. 
I deshed to ascertam, in the first place, whether at the temperature used, any quan- 
tity of carbonic acid, different from its received equivalent, could be expelled by a well- 
known acid of the class of hydrogen acids, as e. g. the sulphuric acid. But as it was 
obviously impossible to experiment with this substance in its usual form, and consider- 
ing that carbonate of magnesia could not exist at the temperature of the experiments, I 
made use of anhydrous sulphate of magnesia for my purpose. 
With this substance I made the following experiments : — 
With Carbonate of Potash and Sulphate of Magnesia. 
No. 
Carbonate of Potash. 
grs. 
Sulphate of 
Magnesia, 
grs. 
Loss= Carbonic 
Acid. 
Equivalent of 
Sulphuric Acid 
deduced. 
I. 
58-14 
27-81 
10-51 
39-4 
II. 
63-99 
32-11 
11-44 
41-0 
Mean . 
. . 40-2 
With Carbonate of Soda. 
Carbonate of Soda. 
I. 
43 
30-27 
11-3 
39-4 
II. 
60-9 
34-46 
12-22 
41 
III. 
67-98 
35-28 
12-63 
40-1 
Mean . 
. . 40-1 
The number 40 is the received equivalent of sulphuric acid. These experiments are 
sufficient to show that with sulphuric acid, at the temperature used, no such effect as 
that with silicic acid is obtained. 
I made several experiments of the same kind with tungstic acid, with boracic acid 
(using, however, biborate of soda for the purpose), alumina, and red oxide of iron. 
Boracic acid only, of the bodies named, afforded results analogous to those given by 
silicic acid, but I did not succeed in obtaining numbers which accorded well together. 
The other substances mentioned gave like results, whether carbonate of potash or soda 
was employed. As alumina appears in some instances to take the place of silica, T will 
insert here the results I obtained with that body. 
The alumina was obtained by Geegory’s process. 
