on the Analysis of the Cag 
357 
utes, and ought never to be omitted, when great accuracy is in 
view. As proving its importance, we may state that in the great 
number of experiments, which we have made within the last few 
months, by the method above described, we have found the 
amount of absorbed carbonic acid, to be rarely less than one twen- 
tieth, and sometimes as much as one fifteenth of a cubic inch; 
varying thus from one twentieth of a per cent. to one fifth of a per 
cent. of the whole weight of that substance contained in the carbo- 
nate employed. 
That the carbonic acid thus united with the liquid, cannot be 
expelled by Rose’s method, is apparent from the fact that its re- 
moval can only be effected by an actual boiling of the liquid, and 
this if attempted in the flask, would lead to far more serious er- 
tors, than that proposed to be corrected.. In proof of the latter 
statement, we would refer to the following experiments. 
Ist. Having prepared a solution with carbonate of lime, and 
the usual charge of dilute hydrochloric acid, and boiled it to ex- 
pel the dissolved carbonic acid, we introduced it into a small bot- 
tle furnished with an ample drying tube, the junctions being all 
Secured air tight. After careful counterpoising at 64°, we heated 
it gradually over a small lamp, until it began briskly to boil: On 
withdrawing it from the lamp, the chloride of calcium was found 
to have been moistened by the condensed steam, for about half 
the length of the tube. The original temperature restored, the 
instrament was placed in the scale. It had lost five tenths of a 
2d. Supposing that this loss might be due to the escape of hy- 
drochloric acid, we made a similar trial with sulphuric acid, and 
found the reduction of weight to be about six tenths of a grain. 
3d. Still further to assure ourselves that the hydrochleric 
acid had not escaped in the former experiment, we renewed the 
charge, and while heating the liquid, passed the vapor and air, as 
they escaped from the drying tube, through a solution of nitrate 
of silver in a test glass, No impression was made upon the test 
Solution, up to the period’ at which the former experiment was 
discontinued. But as soon as the whole length of the drying 
ube was moistened by condensed vapor, the escape of hydro- 
thloric acid was indicated by dense curds of the precipitated chlo- 
tide. A like trial’with the sulphuric solution gave, even earlier, 
the same result, the sulphuric acid carried over with the steam, 
