134 Letter to the Editor, by Dr. Henry. 
The illustrious author of the Elements of Chemical Philosophy will not, 
T trust, require any assurance from me, that nothing could be farther from 
my design, or more repugnant to my feelings, than to misunderstand 
“intentionally” his ideas respecting chemical combination. I have, it is 
true, rendered the word proportion by that of atom, but I have enclosed 
the latter word in parentheses, purposely to shew that it was not the ex- 
pression of the author, but my own interpretation of his meaning. The 
fact is, that great ambiguity has arisen out of the use which has been made 
of the word proportion. Strictly, the only numerical expressions of pro- 
portion, that can be considered as “‘ the results of experiment,” must be de- 
rived from a comparison either of the weights, or of the volumes, in which 
bodies unite ; and it appears to me that a system of numbers, derived from 
the consideration of weights, should be kept distinct from one derived from 
aw comparison of volumes. But the numbers (1 and 15) representing hydro- 
gen and oxygen, were gained from the joint consideration of the weight 
and volume of the elements of water ; while those representing oxygen and 
nitrogen (15 and 26) were derived from a comparison of the weights only 
of the elements of nitrous oxide. Since, then, the word proportion could 
not, in both cases, apply to a comparison of weights only, nor yet of vo- 
lumes only, it was natural for me to conclude that it must bear a reference 
to ultimate particles or atoms, the only other objects, which I could con- 
ceive as, in this case, admitting of being compared. 
These, Sir, are the only points respecting which I deem it necessary to 
trespass on the attention of your readers, though there are others on which 
1 am not disposed to concede the justice of the reviewer's strictures. In 
some instances, I allow, he has pointed out mistakes that may call for cor- 
rection on a future occasion, should any occur to me. Having invited the 
communication of errors or omissions, with a view to the improvement of 
my volumes, it would ill become me to feel “ offended” when that invitation 
is complied with ; and all that I claim is to be animadyerted upon with a 
reasonable share of courtesy and of candour. 
Tam, Sir, 
Your obedient and faithful servant, 
WILLIAM HENRY. 
