420 Hare's Calorimotor. 



a hollow brass cylinder, having the internal diameter two 

 inches, and the outside of another smaller cylinder of the same 

 substance, were made conical and correspondent, so that the 

 greater would contain the less, and leave an interstice of about 

 one-sixteenth of an inch between them. This interstice was 

 filled with wood, by plugging the larger cylinder with this ma- 

 terial, and excavating the plug till it would permit the smaller 

 brass cylinder to be driven in. The excavation and the fitting 

 of the cylinders was performed accurately by means of a turn- 

 ing lathe. The wood in the interstice was then charred by ex- 

 posing the whole covered by sand in a crucible to a red heat. 

 The charcoal, notwithstanding the shrinkage consequent to the 

 fire, was brought into complete contact with the inclosing me- 

 tallic surfaces by pressing the interior cylinder further into the 

 exterior one. 



Thus prepared, the interior cylinder being made to touch 

 one of the Galvanic surfaces, a wire brought from the other 

 Galvanic surface into contact with the outside cylinder, was 

 not affected in the least, though the slightest touch of the 

 interior one caused ignition. The contact of the charcoal with 

 the containing metals probably took place throughout a superfi- 

 cies of four square inches, and the wire was not much more 

 than the hundredth part of an inch thick, so that unless it were 

 to conduct electricity about forty thousand times better than 

 the charcoal, it ought to have been heated ; if the calorific 

 influence of this apparatus result from electrical excitement. 



I am led finally to suppose, that the contact of dissimilar 

 metals, when subjected to the action of solvents, causes a 

 movement in caloric as well as in the electric fluid, and that 

 the phenomena of Galvanism, the unlimited evolution of heat 

 by friction, the extrication of gaseous matter without the pro- 

 duction of cold, might all be explained by supposing a combi- 

 nation between the fluids of heat and electricity. We find 

 scarcely any two kinds of ponderable matter which do not ex- 

 ercise more or less affinity towards each other. Moreover, 

 imponderable particles are supposed highly attractive of pon- 

 derable ones. Why then should we not infer the existence of 

 similar affinities between imponderable particles reciprocally 1 



