Chemical Apparatus. 357 



pie of brass, ground to fit, air tight, in a brass collar cemen- 

 ted upon the neck of the vessel. On one side of the gun 

 barrel, a flexible lead pipe, P, with a cock, is soldered into 

 a perforation in the stopple, which enables it to communi- 

 cate with the interior of the globe. In like manner another 

 tube is soldered into the stopple, which establishes a com- 

 munication between the cavity of the uninflated bladder, B, 

 and that of the globe. Into a tubulure, T, another larger 

 pipe is luted, so that while one part proceeds, within, to the 

 bottom of the vessel, the other is surmounted without, by a 

 cock and funnel. The gun barrel is closed at the lower end 

 — at the upper end is open. Near the lower end is soldered, 

 a cup of sheet copper, perforated so as to allow the gun bar- 

 rel to pass through it for about an inch. 



On this cup, the phosphorus in small pieces is placed, and 

 the bottom of the vessel being covered by water, the stopple 

 is seated in the brass collar, as seen in the figure. The 

 cocks being all shut, the phosphorus is heated through the 

 gun barrel by a red hot iron, I, passed down the bore of the 

 barrel, until the heated part is opposite the copper cup. As 

 soon as the combustion begins, the hot iron should be with- 

 drawn ; but when the flame burns dimly, the iron, mean- 

 while, returned into the fire, must be again applied, to sup- 

 port the temperature, until all the oxygen may have united 

 with the phosphorus. At the commencement of the com- 

 bustion, the bladder is inflated in consequence of the expan- 

 sion of the air arising from the heat ; but, as the volume of 

 the air is reduced, about one fifth, by the condensation of 

 its oxygen, and as the heat causing the expansion escapes, 

 the air which had inflated the bladder, returns into the globe. 

 Its return should be accelerated and completed, by compres- 

 sing the bladder, the neck of which, while compressed, should 

 be tied. Water should then be introduced through the fun- 

 nel, the cock being opened for the purpose, until the deficit 

 caused by the loss of oxygen, be compensated. By the in- 

 troduction of a farther quantity of water, any requisite por- 

 tion of the gas may be made to flow out, through the pipe, 

 P ; which, in the original, is long enough to reach under the 

 sliding shelf of the pneumatic cistern. 



