154 Defer iptlon of a new Gas- bolder. 



two tin fockets by corks at the top and the bottom of the. 

 gas-holder, into which it opens at both ends: of courfe the 

 level of the water in the apparatus will always be feen in the 

 tube, and confequently that of the gas. 



C, the circular cifiern, with its two cocks and pipes, 

 marked i and 2. 



Ck, a brafs cock on the fide, with a fcrew, to which blad- 

 ders or a blowpipe may be attached. 



O, an opening into the gas-holder, in which a pipe is fol- 

 dered at fuch an angle, that when all the uppermoft cocks 

 are fhut no water can poffibly efcape. But when a conducl- 

 ing-pipe, from a retort or other apparatus generating gas, is 

 introduced into this opening, then, as the gas paffes up into 

 the gas-holder, an equal quantity of water will be difcharged 

 at O into any veffel fit to receive it. 



Sp, a fpout on the fide of the cittern to enable the ope- 

 rator to add water even when the receiver fills its whole area. 



HH, handles to lift the gas-holder by. 



He, a glafs deflagrating receiver ffcanding in the cifiern. 



A, its adopting cork and cock. 



S, a watch fpring in a flit wire prepared for combuftion. 

 The wire paffes through a cork. 



D, a deflagrating difh of iron for fulphur, phofphorus., 

 bark of charcoal, fugar, camphor, &c. 



B, a blowpipe, with a gum elaftic tube E/capable of join- 

 ing the cock Ck. 



To make ufe of this apparatus, firft fill the gas-holder with 

 water, by clofing the opening O with a cork, and alfo the. 

 cock Ck, and keeping the circular ciftern full of water, while 

 the cocks I and 2 are both open. The air is driven out of 

 the gas-holder through the cock 1, by the water defcending 

 into it by the cock 2. When full, the water in the regifter 

 will be on a level with the top of the gas-holder. Then 

 fhut the cocks 1 and 2. You may now remove the cork from 

 the opening O, which is then prepared to receive the ccn- 

 du&ing-pipe from any apparatus from which the gas is ge- 

 nerating. As the gas is delivered the water efcapes, and 

 fhoukl be caught in any convenient vefl'el. The regifter will 

 then (how the quantity received: when full, clofc the open- 

 ing O with a cork wrapped in leather, which prevents the 

 communication with the atmofpherc. [t may now be eafily 

 removed or conveyed where it is wanted. 



When it is required to fill a glafs receiver, as Be, with 

 the gas, having previoufly filled the circular ciftern with 

 water, place it in the ciftern, put in the adopting cork A, 

 and, with the mouth applied to the cock, exhauft the re- 

 ceiver, in which the water will rife till full. Then dole the 



cock 



