NATURE AND THEOREMS OF HEAT. t»3

All the effects of heat according to this theory, depend there-fore entirely on the vibratory motion of the particles of bodies.According as this is more or less intense, a higher, or lower tem-perature is produced; and as it predominates over...is nearlyequal...or inferior to the attraction of cohesion, bodies exist in thegazeous, fluid, or solid state.

Different bodies are susceptible of it in different degrees, andreceive and communicate it with different celerity. From thegeneration, communication and abstraction of this repulsive mo-tion under these laws, all the phenomena ascribed to heat areexplicable.

Each of these theories has been supported by the most ablephilosophers, and given occasion to the most important disputesin which chemists have been engaged; and have contributed ina very particular manner to the advancement of the science.The obscurity of the subject however is such, that both partieshave been able to advance the most plausible arguments.

Setting aside all enquiries concerning the merits of these dif-ferent doctrines, we shall confine ourselves to the general effects,which heat produces on different bodies. For the phenomenawhich heat presents, and their relation to each other, may beinvestigated with sufficient precision, though the materiality, orimmateriality of it, may remain unknown to us.

NATURE AND THEOREMS OF HEAT.

This premised, those who consider heat as matter, assert thatcaloric exists in two states, namely, in combination, and in aradiant state or at liberty.

In the first state it is not sensible to our organs, nor indicatedby the thermometer; it forms a constituent part of the body;but it may be brought back to the state of radiant or sensibleheat. In this state it affects animals with the sensation of heat.It therefore has been called sensible or free heat, or fire; and issynonimous with uncombined caloric, thermometrical caloric.