44jS Dr. Henry’s Experiments on Ammonia. 
There can scarcely be a doubt, however, that this want of 
coincidence is owing to the same cause, as that which I have 
already assigned for the variable proportions of permanent 
gas, which are obtained from equal quantities of ammonia by 
electrization. And, accordingly, I have found that the evolved 
gases, as ascertained by combustion, bear the smallest pro- 
portion to the ammonia, when most pains have been taken to 
obviate the presence of moisture. The lowest number, there- 
fore, is to be assumed as most correct ; but other circumstances 
being considered, I believe the second experiment furnishes 
the most accurate data for determining the composition of 
ammonia. The same explanation will apply to the different 
proportions of oxygen gas required for the saturation of 100 
measures of ammonia, the variation no doubt arising from the 
uncertainty of the quantity of alkaline gas which is actually 
burned. The proportion of oxygen to ammonia, which I be- 
lieve to be nearest the truth, and most precisely necessary for 
mutual saturation, is that resulting from the second experi- 
ment, viz. 6y~ measures of oxygen gas to 100 of ammonia, 
or 100 of the former to 148 of the latter. 
It may be observed, also, by comparing the numbers in the 
two last columns of the table, that the hydrogen and nitrogen 
gases do not uniformly bear the same proportions to each 
other. Notwithstanding all the labour I have bestowed on the 
subject, I have not been able to obtain a nearer correspond- 
ence, owing most probably to the imperfection of the mode 
of analyzing a mixture of hydrogen and nitrogen gases. In 
the mixture of permanent gases, determined in this way, the 
hydrogen, it may be remarked, bears generally rather a less 
ratio than that of 74 to 2 6. I do not, however, consider this 
