356 



Chemical Apparatus. 



smaller than the other, and surmounting it in an inverted 

 position. The brass plate which covers the orifice of the up- 

 per bell, is so fitted to it, as to form an air tight juncture, and 

 is furnished with a cock terminating in a gallows and screw, 

 for attaching a leaden pipe proceeding from an air pump. 

 A hook is soldered to the lower surface of the plate, from 

 which some leaves of Dutch gold* are suspended. Suppose 

 the lower bell to be filled with chlorine over the hydropneu- 

 matic cistern, the upper one exhausted by the air pump. On 

 turning the cock, the chlorine will rush into the upper bell, 

 and cause the instantaneous combustion of the included leaf 

 metal. Afterwards the upper bell will be replete with the fumes 

 of the resulting chlorides, of the metallic matter of the alloy. 

 Apparatus for procuring nitrogen. 



Apparatus for abstracting the oxygen from atmospheric air, 

 and leaving the nitrogen so situated, as to be drawn easily 

 from the containing vessel, in such quantities, and at such 

 times, as may be desirable. 



Concentric with the axis of the globular glass vessel, A, 

 is a portion of a gun barrel, which is soldered to a large stop- 



* An alloy of copper. 



