Saturaiteti e/ Alkali ivlth Carhonic AclJ. 37 1 



nrck h is then to be ftopped with its cork, and by blowing through the tube K the alkali is- 

 to be forced through the fyphon g' g into the bottle D. The air contained in this laft bottle 

 efcapcs through the tube a a' a, and pafles through the water of the fmall bottle d. The 

 fluid becomes nearly on a level in the bottles D and /, and the extremity of the tuhefffy. 

 which conne£ts the bottles B and D, is plunged in the alkali. — Proceeding then to the part 

 c, the cock m of the inverted veflel is to be opened, while that of the tub r is kept {hut. By the 

 ^xcefs of weight of the jar beyond that of K it finks in the tub, and becomes filled with water^ 

 while the common air it contained efcapes at g. — As foon as the inverted veflel, being to- 

 tally immcifed in the tub, repofes on the circular fegments ///, the orifice of the upper 

 tube of the tube b is found in the brafs receptacle /. It is neceflary, that the level of the- 

 water, which by the immerfibn of the inverted veflel may have rifen from e to e', fhould 

 have the elevation ^^'of the tube b equal at lead to two centimetres higher,in order that this- 

 tube may not be clofed by the water, which would prevent the gas from entering into the 

 veflel C. — When this laft veflTel is full of water, its cock / muft be fliut, and the cock r of the 

 caflc muft be opened- 



In this difpofition of the apparatus, the glafs ftem/"of the part A is to be raifed, and 

 carbonate of lime gradually introduced, which falling upon the fulphuric acid becomes 

 decompofed, and lofesits carbonic acid. Thislafl: poflefling the elaftic ftate, pafl"es through' 

 the tube h h h into the bottle B. The tube d is then to be raifed, in order that the atmo- 

 fpheric air contained in the bottles A and B may flow out ; after which, the neck a of the 

 bottle B is to be clofed, by replacing tube d. In this fituation the carbonic acid gas, which; 

 enters B, (meeting lefs refiftance in its paflage to the inverted veflel through the tubes f r 

 and 000, than to pafs into the part D by the tube fff, which is plunged in the alkali) raifcs- 

 and fills the vefl"el c. — As foon as this event has happened, no more carbonate of lime is to- 

 be introduced into the bottle A, and the bottle D is filled with alkali by blowing through 

 tlie tube K of the bottle /. The levels of the alkaline fluid are at the height n in the bottle- 

 D, and m < « in the bottle / ; and the fluid tending to its level, by means of the fyphoni 

 gg', the furface « falls, and produces a vacuum in the bottle D. — ^The carbonic acid gas is^ 

 then drawn into the bottle D by the tube///'; at the fame time that the water of the fmalli 

 bottle d (part D) rifes in the tube a a' a; but the height of this tube is fuch, that the car- 

 bonic acid gas can enter the bottle D before the water rifes to a' in the tube a a' a., — The- 

 two furfaces « and m acquire an equilibrium in the bottles D and /, and the carbonic acid 

 gas, which occupies the upper part of the bottle D, combining with the pot-afh, a vacuum 

 is formed, which is continually fupplied with new gas. — When the veflel C is nearly cx« 

 haufted of its gas, it muft be filled by a new difcngagement. 



N. B. As the carbonic acid gas is mixed with a fmall portion of atmofphericair, this air^, 

 which is not abforbed by the pot-afli, accumulates in the bottle D, and may flop the ope- 

 ration. It muft be driven out by blowing into the tube 3 of the bottle/, and filling the- 

 bottlcL D- with alkali. 



XV. JhflraSff 



