FIG. 2. 



(a be) The section of the plates, (as in Fig. 1.) 



(d) The magazine jar. 



(e) The small jar. 



(/) The dotted jar shews how the small jar is placed, together with 

 the third plate (c), before it is slided across the edges (g) 

 of that and the upper plate. 



FIG, 3. 



(« If c) The plates as before, but fixed in 

 (/z) The frame. 



(d) The lower or magazine jar, (as in Fig. 2.) wedged up against 



the under pktc, by 

 {k) The moveable bottom. 



(e) The small jar to be filled with gas from the lower jar. 



FIG. 4. 

 A SMALL APPARATUS FOR OPERATING WITH MERCURY. 



(« b c) The plates as before. 



{d) The small jar, four inches high, with a broad rim, by which the 

 lower plate may be confined to its mouth, together with a 

 frame in which the upper and third plates may slide. This 

 frame may be made of hard wood, of ivory, or of iron. 



