on the Analysis of the Carbonates. 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 

 effervescence, in the cotton packing, at the inner ends of 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- 

 ric 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. 





