1815.] On Tungsten. i 
rendered still stronger in consequence of a conversation which I had 
with the celebrated naturalist Professor Steffens, of Halle, who 
seemed to doubt the accuracy of the statements respecting the great 
specific gravity of tungsten. The following dissertation contains 
my experiments and their results as far as the time I had would allow 
me to follow themup. The continuation of them will follow. 
(A.) 
Experiments on the best Method of forming Tungstic Acid, or rather 
Tungstate of Ammonia. 
As my object in these experiments was in the first place, for very 
obvious reasons, directed towards the reduction of tungsten, and as 
I wanted to verify the statement of Allen and Aikin that this metal - 
may be fully melted by the application of a violent heat to tungstate 
of ammonia, on that account my first care was to discover a conve- 
nient method of obtaining a sufficient quantity of tungstate of am- 
monia. It was quite natural to try in the first place Scheele’s tung- 
stic acid, composed of oxide of tungsten, potash, and muriatic acid, 
because I had a considerable stock of it in my possession. 
+ Exper. 1.—With a view to the statement of several chemists, 
who affirm that in order to form pure tungstate of ammonia it is 
necessary to separate the pure yellow oxide of tungsten from 
Scheele’s tungstie acid by digestion in nitric acid, I made the fol- 
lowing experiment :—Two ounces of the triple compound of tung- 
stie oxide, potash, and muriatic acid, were triturated with eight 
ounces of pure nitric acid of the specific gravity 1°200; and being 
put into a glass vessel capable of holding 16 oz. of water, were. 
boiled for six hours, and during that time were frequently agitated. 
This process was very difficult, because the salt and oxide settling 
at the bottom of the vessel occasioned a continual knocking of the 
vapour, and by that means the acid was sputtered about. The oxide 
obtained by this process was very light yellow, without the least 
shade of lemon. This entitled me to conclude that the triple salt 
had not been completely decomposed. ‘To obtain a more complete 
decomposition, the whole was poured into a porcelain dish, and 
evaporated on the sand-bath to the consistence of a syrup, being 
constantly stirred during the whole process by a porcelain spatula. 
The whole was then diluted with 12 0z. of water, and after re- 
maining at rest for 24 hours, the milky solution was separated from 
the heavy yellow oxide. This oxide was treated ir the same way 
in in the porcelain dish with 6 oz. of nitric acid. The oxide 
tained in this manner, and three times washed with 45 oz. of water, 
was considered by me as pure. When dried, and heated to redness, 
it assumed a light yellow colour, and weighed 13 drams. After 
piece weeks, 90 gr. of the same oxide precipitated from the milky 
iguid. 
With this oxide the following experiment was made. 
Exper. 2.—300 gr. of the tungstic oxide which had been heated 
