on the Analysis of the Carbonates. 



351 



tubes, the one horizontal, the other vertical, both projecting a 

 short distance into the bottle. It is also penetrated centrally by 

 a stout platinum wire about four inches long, hooked at the low- 

 er and bent twice at the upper end. A thin glass bucket for con- 

 taining the solid carbonate, is represented in the figure as hang- 

 ing within the bottle. This is perforated at bottom, and furnish- 

 ed with a handle of platinum wire, to allow of its suspension 

 from the upper and from the lower hook, in the successive stages 

 of manipulation. Such is the arrangement we employ in exper- 

 iments with carbonates of lime, baryta and soda, and the other 

 carbonates which admit of accurate weighing while exposed. 



2SES30- 



ln the second form, the platinum wire and glass bucket are omit- 

 ted; the carbonate enclosed in a thin, sealed tube, is placed at the 

 bottom of the bottle, and the hydrochloric acid retained until need- 

 ed in the globular pipette above. The latter appendage, drawn 

 out to a delicate and even tube below, is inserted through the 

 centre of the cork, and projects into the bottle about three fourths 

 of an inch. As in this arrangement, which is free from the errors 

 incident to the use of the gum-elastic bag, the column of acid is 

 exposed to an undiminished atmospheric pressure at top, some 

 care is necessary in forming the tapering stem of the pipette, oth- 

 erwise the liquid will escape in drops during the first weighing. 

 This is obviated by a very gentle convergence of the tube, and 

 by drawing in a column of air 3 so as to fill the lower half, or two 



