Hare’s Calorimotor. 423 — 
EXPLANATION OF THE PLATE. : F 
A a, Fig. 1st, two cubical vessels, 20 inches square, inside. 
bbb baframe of wood containing 20 sheets of copper, and 
20 sheets of zinc, alternating with each other, and about half 
an inch apart. T Tt ¢ masses of tin cast over the protruding 
edges of the sheets which are to communicate with each other. 
Fig. 2, represents the mode in which the junction between 
the various sheets and tin masses is effected. Between the 
letters z z, the zinc only isin contact with the tin masses. 
Between cc, the copper alone touches. It may be observed, 
that, at the back of the frame, ten sheets of copper between 
cc, and ten sheets of zinc between zz, are made to commu- 
nicate, by a common mass of tin extending the whole length of 
the frame, between TT: but in front, asin fig. 1, there is an 
interstice between the mass of tin connecting the ten copper 
sheets, and that connecting the ten zinc sheets. The screw 
forceps, appertaining to each of the tin masses, may be seen 
on either side of the interstice; and likewise a wire for 
ignition held between them. The application of the rope, 
pulley, and weights is obvious. The swivel at S permits the 
frame to be swung round and lowered into water in the vessel 
a, to wash off the acid, which, after immersion in the other 
vessel, might continue to act on the sheets, encrusting them > 
with oxide. Between pp there is a wooden partition which 
is not necessary, though it may be beneficial. 
Fig. 3, represents an apparatus alluded to, page 419. It 
consists of a couronne des tasses, reduced to a form no less 
compact than that of the trough. Hollow parallelopipeds of 
glass are substituted for tumblers or cells. The plates are 
suspended to bars counterpoised like window-sashes. f 
The advantages are as follows. The material is one of the 
best non-conductors, is easily cleansed, and is the most imper- 
vious to solvents. The fracture of one of the cups is easily 
remedied by a supernumerary. They may be procured (as 
in the United States) where porcelain cannot be had. The 
shock from 300 pairs is such as few will take a second time. 
Some of the effects have already been stated.* 
At Fig. 4, one of the hollow glass parallelopipeds on an 
enlarged scale is represented. 
* The glasses may be had by applying to Edw. A. Pearson, No. 71 Cornhill, 
Boston. 
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