88 APPARATUS FOR THE ANALYSIS OF GASSES. 



the cistern «, and quickly inverted over the burner t. By 

 a little practice, this may be done with the admission of very 

 little common air. A transferring vessel is then screwed 

 upon the cock f; and a portion of oxigen gas removed for 

 eudiometrical examination. To allow room for the expan- 

 sion of the oxigen gas, the water is raised by a siphon to a 

 proper height within the receiver b, as appears in the draw- 

 ing, 

 and of conduct- The apparatus being thus disposed, the cock f is con- 

 tinent, nected by the chain h with the prime conductor of an elec- 

 trical machine; and a rapid succession of sparks is made to 

 pass between the copper ball at the end of the wire g, and 

 the orifice of the burner. The cocks q and r being now 

 opened, the stream of gas is kindled ; and in order to pre- 

 vent the flame from playing upon the wire, the jar n n is 

 moved a little nearer to the cistern a, which brings the point 

 of the burner into the axis of the receiver. At the same time, 

 by opening the cock x, water flows into the jar n w, and finds 

 its way into the receiver, through two small holes w iv drilled 

 near its mouth. 



The combustion continues, until either the whole of the 

 inflammable gas is consumed, or till the cocks q and r are 

 shut. The wedges v v are removed ; the receiver o o un^ 

 screwed ; and the bent tube removed from its place* It is 

 at this moment, that the cock r is useful, by preventing the 

 escape of the gas from the receiver b through the tube s s. 

 The upper part of the receiver is cooled by the application 

 Calculation of of a wet sponge. Without waiting, however, till the gas 

 the results. j^ Gained the temperature of the atmosphere, a very small 

 and sensible thermometer is introduced into it; and the 

 height of the mercury is noted, as soon as it becomes sta- 

 tionary. The volume of the residuary gas is then observed, 

 and is reduced by calculation to the bulk, which it would 

 occupy at 60° of Fahrenheit. Either the whole, or an ali- 

 quot part of it is removed by a transferring vessel, screwed 

 upon the cock f> to a mercurial cistern, where the propor- 

 tion of carbonic acid is determined by liquid potash. The 

 proportions of oxigen and nitrogen gasses, in the unabsorbed 

 residue, are learned by agitation with sulphuret of lime, 

 observing the precaution* which have been stated by de 



Marti. 



