196 
I had worked a good deal with the mixed gases, but 
lately thought it better to return to the simple, although 
unwilling to question results got by others. Five of 
these gases have been tried, and they are found to be 
absorbed by charcoal in whole volumes and not in fractions 
of a volume, hydrogen being taken as one. In three cases 
hydrogen, oxygen, and carbonic acid, the numbers are 1, 
7'99 and 22D 5 extremely exact volumes, with a relation 
the same as our ordinary atomic weights. Saussure’s 
numbers treated thus give 5 -3 and 20, that for nitrogen 
being 4*2. 
It is only by taking the average of many experiments 
that these results have been obtained, but, in doing so, 
every one has been added without selection. The numbers 
from which the averages are obtained diverge so much that 
I suppose others have not thought of obtaining anything 
definite. This is caused by the difficulty of finding perfectly 
uniform charcoal. 
I have not found the other numbers to be the same as 
the equivalent, although still whole. Equivalents promise 
here to enlarge their bounds. I cannot believe that these 
numbers can be the results of any accident. They must be 
distinguished from chemical equivalents by weight. 
I am, 
Yours sincerely, 
R. Angus Smith. 
J. P. Joule, Esq., L.L.D., F.R.S., &c. 
