318 Hare’s Eudiometers, &¢. 
A A, acistern divided by a water tight partition, which 
separates the air holder G, from a calorimotor situated un- 
der C, and a plunger P, contained in the other part of it. 
W W, wires severally s soldered to the different galvanic sur- 
faces, and forked or slit at their ends, so as to embrace the 
wire of an eudiometer for the explosion of inflammable 
mixtures, as mentioned in the preceding article. At ff, are 
forceps (severally soldered in the same way) for holding a 
wire to be ignited by the galvanic influence. 
These wires and the plates with which they are connect- 
ed may be seen at fig. 5, where there is an enlarged drawing 
of the calorimotor and its wires. 
It is supposed to be situated below the edge of the cis- 
tern, which is supplied with diluted acid reaching within a 
little distance of the plates. 
c, a cock soldered toa pipe communicating with the in- 
side of the gasometer. hh.a gallows and guide wire, for 
regulating the rise of the gasometer. 
The construction of this will be better comprehended 
from fig. 6, where t represents the tray for holding the zinc, 
by means of which hydrogen is to be evolved. ‘The tray 1s 
supported on the pipe in the axis of the vessel by a sliding 
band and screw, so that it may be raised or depressed at 
pleasure. When this tray is covered with granulated zine, 
and the lower vessel is filled with acid so as to cover it, ’ 
hydrogen must be generated until it occupies so much of 
the air holder, as to depress the acid from off the zinc. 
Supposing the apparatus thus prepared, on depressing the 
plunger at P, fig. 4, the acid in the cistern A A, will be 
forced up among the galvanic surfaces, and cause the wire | 
at ff to be ignited. ‘Turning the cock while the wire is 
ved hot the hydrogen will be emitted and inflamed. 
