on the Analysis of the C 359 
submit every step of the operation to the severest scrutiny. Most 
of the results of this test examination have already been stated, 
and we will merely add that the important fact of the non-escape 
of any of the hydrochloric acid, either during the effervescence, 
or in the process of aspiration, of which we early satisfied our- 
selves by direct experiments, has been still more conclusively 
proved by the constant use of the test bottle in the numerous 
analyses we have since performed. As an index of how entirely 
the acid is retained within the instrument proper, we would call 
attention to the fact that a solution of nitrate of silver, which has 
been used by us in the test bottle during the last ten or more op- 
erations, and through which more than eight hundred cubic 
inches of air, after passing over the acid liquid, has been slowly 
transmitted, is as unclouded now as when first placed in the ves- 
sel. The chief agency in thus arresting the‘ hydrochloric acid, 
is due to the moisture deposited by the carbonic acid, during the 
eflervescence, in the cotton packing, at the inner endsef the dry- 
ing tubes, and we have found that when the cotton is quite dry 
and the aspiration is made from a bottle containing only hydro- 
chloric acid, traces of this soon show themselves in the test tube. 
Cotton fibre even when dry is capable, according to our experi- 
ments, of absorbing twice its weight of the acid vapor, but when 
moistened, even no more than by exposure to the damp breath, 
its absorbent power is very greatly increased. It appears there- 
fore, that no fears need be entertained of the escape of hydrochlo- 
tic acid vapor, where the test tubes are charged as above describ- 
ed; and we are therefore at liberty to use this acid in the numer- 
ous instances where its employment would in all other respects 
be preferred. 
In conclusion we would beg to say, that we have been led to 
enter thus minutely into many of the details of the processes here 
described, because we believe that by them we shall be enabled 
to investigate with unlooked for accuracy, the equivalents of a 
large number of substances, and because we desire that all the 
Particulars of the methods we adopt, should be submitted to the 
criticism of experienced chemists. 
