APPARATUS FOR THE ANALYSTS OF GASSES. 87 



way to experiment, are extremely minute; and the inflam- Experiments 

 mation of highly combustible gasses is attended, as I have d . inger , 

 more than once experienced, with considerable danger from 

 the bursting of the glass tubes. It was desirable, therefore, 

 to employ a process not liable to these objections; and after 

 many alterations of the apparatus, contrived with this view, 

 I at length fixed upon one, which I shall now proceed to 

 describe. 



The principal parts of the apparatus, are two glass cylin- Apparatus 

 ders, or air receivers*, bb and o o, PI. IV, of which the lhe ana i ys i s , 

 larger one is intended to contain oxigen gas, and the smaller described. 

 one, the inflammable gas submitted to experiment. They 

 are connected by a bent glass tube s s, the diameter of 

 which should not be less than T V of an inch, to the upper 

 extremity of which is cemented an iron burner, t 9 the ori- 

 fice of which is about 7 V of an inch, while to the lower end 

 a socket is fixed, on which may be occasionally screwed the 

 cock r. The receiver o o is contained in a larger glass jar 

 n w, and is closed at the top by a brass cap p, and stop cock 

 q. The oxigen gas receiver is also closed by a brass cap e 

 and cock /, the lower orifice of which is tapped internally, 

 for the purpose of receiving a small screw at the end of the 

 copper wire g. This wire is in two parts, each of which 

 screws into a movable socket, connecting the two ; and, by 

 this contrivance, the wire may be lengthened or shortened 

 at pleasure. To prepare the apparatus for use, the receiver Method of prdr 

 o o is partly filled with the combustible gas; and is secured P ar,n S lt f#r 

 by wedges of cork v v, in the jar n w, the level of the water 

 in the latter being regulated by opening the cock x or z. 

 The bent pipe s *, with its cock r, is screwed upon the top 

 of the receiver, and partly immersed in the water of a pneu- 

 matic cistern, a «, so that the orifice of the burner may rise 

 a few inches above the surface of the water. The receiver 

 b b 9 detached from the situation in which it is represented 

 in the drawing, is then exhausted by an airpump; and, 

 being filled with oxigen gas, is transferred (its mouth being 

 closed during the act of removal with a piece of leather) to 



* I am indebted to Mr. H Creighton, of Soho, not only for a draw- 

 ing of the apparatus, but for much raluable assistance in tht perform- 

 ance of the experiments. 



the 



