160 



well as stout tubes, might, as he had found, be softened and extended, 

 or bent into suitable forms. 



The lower end of a green glass phial, such as is used usually for 

 Cologne water, might be made to draw out into a trumpet-shaped extre- 

 mity. A Florence flask might be heated, and made flat, so as to an- 

 swer better for some purposes. The drawing out of tubes into a 

 tapering form, suitable for introducing liquids through retort tubulures, 

 was thus easily effected; and in all cases the sealing of large tubes 

 was better commenced in this way, although the blowpipe might be 

 necessary to close a capillary opening which could not be closed by 

 the fire. 



Dr. Hare further communicated a method of preparing 

 pure chlorohydric acid, from the impure muriatic acid of com- 

 merce, by the action of sulphuric acid. 



It is known, said Dr. Hare, that concentrated sulphuric acid, when 

 added to liquid chlorohydric acid, expels more or less of it as a gas, 

 in consequence of its superior affinity for water. At the present low 

 price of the ordinary acid of commerce, Dr. Hare had found it ad- 

 vantageous to procure the latter in purity, by subjecting it to the for- 

 mer. 



A tubulated glass retort, having been half-filled with chlorohydric 

 acid, sulphuric acid was allowed to drop from a glass funnel, with a 

 cock, into a tube descending into the acid in the retort through the tu- 

 bului'e, to which it was luted by strips of gum-elastic. The tube ter- 

 minated in a very small bore. The beak of the retort, bent in the 

 fire, as he had just described, descended through the tubulure into 

 the body of a small retort containing water not refrigerated. The 

 beak of the latter descended into a larger one, half full of water, to 

 which ice was applied. Of course the beak of the third might, in like 

 manner, enter the body of a fourth. After an equivalent weight of 

 sulphuric acid had been introduced, and the evolution of gas was no 

 longer sufficiently active, heat might be applied until nearly all the 

 chlorohydric acid should come over. 



The residual diluted sulphuric acid was, with the addition of nitrate 

 of soda or potassa, or nitric acid, as serviceable for galvanic purposes, 

 as if it had not been thus used. 



Dr. Hare further communicated a method of preparing hy- 

 drochloric acid and chlorine in the self-regulating reservoir 



