316 Hare’s Eudiometers and Calorimotor. 
eter. ‘The whole is cemented into the perforation drilled 
in the tube, so as that the smallest part may extend across 
the bore. The wire should then be cut off at about one 
third of an inch from the tube, so as to stand out from it 
on each side about that distance. If these protruding wires. 
be severally placed in the forceps of a calorimotor and the 
plates subjected to an acid, the small part of the wire within 
the tube is vividly ignited, and any gas in contact with it 
must explode. The interior wire is best made of platina, 
and may in that case be screwed into two larger pieces of 
a baser metal ; or a baser metal may be fastened on it, by 
drawing through a wire plate, and the platina duly denuded 
by a file where it crosses the bore. 
The calorimotor which I have used for this purpose, con- 
sists of eleven plates of copper, and a like number of zinc, 
placed alternately within one-fourth of an inch of each 
other ; those of the same kind of metal being all associated 
by means of a metallic stratum of tin cast over them. The 
two heterogeneous galvanic surfaces thus formed, have each 
soldered to them a wire in a vertical position, and slit, so 
as to present a fork or snake’s mouth. The wires are just 
so far apart as to admit the gas measurer between them, so 
that the wires of the latter may easily be pressed into the 
vessel, until it nearly reaches the plates. A plunger, con- 
sisting of a water tight box, or solid block of wood, is then 
This apparatus may be constructed in the circular form, 
by so placing two concentric coils, or several concentric 
