432 Dr. Henry's Experiments on Ammonia, &c. 
dried by sticks of pure potash, fastened to pieces of steel wire,, 
so that they could be withdrawn, after having exerted their 
full action. This point of dryness was ascertained by apply- 
ing aether, or a mixture of snow and salt, to the outside of 
the globe. By means of a peculiar apparatus, the gas wa3 
next strongly electrified, and the cooling power was again 
applied to the outer surface of the globe. 
In the first trials, that were made with this apparatus, water 
certainly seemed to have been formed by the electrization of 
the alkaline gas ; for the same portion of gas, which was not 
affected by a freezing mixture before the process, gave evi- 
dent signs of condensed moisture, when the cooling power 
was applied after long continued electrization. The appear- 
ance was not only quite satisfactory to myself, but to Mr. 
Dalton, and several other chemical friends, to whom I shewed 
the experiment. Finding, however, that the appearance va- 
ried as to its degree, I was induced to repeat the process with 
redoubled precaution ; filling the globe, previously heated, 
with hot mercury, and drying not only the quicksilver, but 
the iron cistern which contained it, by exposure to long con- 
tinued heat. The electrified gas now betrayed no signs of 
moisture on the application of a temperature so* of Fahren- 
heit; and gave only the smallest perceptible traces, by a 
cold of o° or a few degrees below. I cannot help suspecting, 
therefore, that the moisture, manifested in the earlier experi- 
ments, was derived from the mercury or from some extra- 
neous source, and was not generated by the action of elec- 
tricity.* 
* It may be objected, I am aware, that as the gases produced from ammonia are 
nearly double its original bulk, they may hold in combination any water that may 
