t 43° H 
XVI Experiments on Ammonia, and an Account of a new 
Method of Analyzing it , by Combustion with Oxygen and other 
Gases ; in a Letter to Humphry Davy, Esq. Sec. R. S. &c. 
from William Henry, M D. , F. R. S. V. P. of the Lit. and 
Phil. Society , and Physician to the Infirmary, at Manchester * 
My Dear Sir, 
I should sooner have communicated the account, which you 
are so good as to request, of my further experiments on the 
decomposition of ammonia, if I had not been anxious to obtain, 
by frequent and careful repetition of them, results not affected 
by any of those numerous causes of error, which easily insi- 
nuate themselves into processes of so much delicacy. You 
have already been informed that the fact, which I lately men- 
tioned to you, (tending to prove the existence of oxygen as 
an element of the volatile alkali, by the discovery of oxygen 
gas in the products of its analysis ) is not entitled to confidence,, 
owing to the admission of a small quantity of atmospherical 
air, in a way which was not at all suspected. Frequent repe- 
titions of the same process, under circumstances wholly un- 
objectionable, have fully satisfied me, that no portion what- 
soever of oxygen gas is evolved by electricity from ammonia, 
even when, by means of an apparatus constructed for the 
* This letter in its original form, was read to the Society, May 1 8th, 1 809, some 
new observations were added and some corrections furnished by the author, in con- 
sequence of subsequent experiments made in June; it was transmitted to the Secre- 
tary for publication J uly 10. 
