1822.] _ Dr. Prout on Vegetable and Animal Substances. 425 
tifully white crystallized substance (very like oxalic acid in 
appearance), permanent in ordinary states of the atmosphere, 
and without any remarkable taste or smell. I may remark, that 
the above two substances were among the first I analysed, and 
that the analyses were made with a charcoal apparatus much 
less capable of precision than the lamp apparatus which I sub- 
sequently employed. 
The views which I published some years ago respecting the 
atomic theory, seem to be now generally known in this country. 
These views at the time led me to others which I was exceed- 
ingly anxious to verify; and as I was interested, for other rea- 
sons, in the composition of organic substances, it struck me 
that by submitting these substances to analysis, I might not 
only obtain a knowledge of their composition, but by investigat- 
ing the laws which might regulate the union of their elements, 
hydrogen, carbon, oxygen, and azote, be able to obtain an 
insight into the laws which regulate the union of other element- 
ary principles. With these views, therefore, I set to work, and 
after very great labour, and no trifling expence in apparatus, &c. 
succeeded, as | supposed, in analyzing more or less perfectly 
almost every well-defined and crystallized organic substance 
that I could procure. A few of my earlier results were pub- 
lished, perhaps, prematurely, but the great mass, as is well 
known to several of my friends, still remains by me, nor have 1, 
for various reasons, the least inclination to publish them at pre- 
sent. Inthe mean time, however, it may be stated, that the sub- 
stances analyzed were dried at 212° in vacuo with sulphuric acid, 
by means of an apparatus described by me several years ago for 
that purpose, that every precaution (including those men- 
tioned by Dr. Ure as well as others), were taken to insure 
accuracy, that, with the exception of sugar, and one or two 
other substances, every substance analyzed by Dr. Ure and 
‘myself in common appears by the charcoal apparatus to contain 
less carbon than by the lamp apparatus.* 
I am, dear Sir, yours, &c. 
WixtiaM Provrt. 
* In making this remark, I by no means wish to insinuate that Dr. Ure’s results 
are erroneous; my object is merely to show that the lamp apparatus is as capable in 
many instances of oxidizing carbon as the charcoal apparatus. It is probable that seve- 
ral of the substances examined by Dr. Ure could only be analyzed by some such means 
as those he employed; but for the analysis of most substances containing azote, I do not 
hesitate to say that I prefer the lamp apparatus. 
