CALORI C.

BOOK I.

PRELIMINARY CHAPTER.

"O that those who have both time and intellect at command adequate to the investigation, might in perfect tranquillity, search into nature, until they ascertain what quantities of heat are required to produce every action of matter; that mankind might then not only become masters of every kind of knowledge, but of every kind of power." TELESIUS.

THAT the reader may perceive at once the general scope and object of the present work, I shall commence with a brief outline of the leading facts, which connect the various operations of nature with the fundamental laws of caloric. But as men of science are still undecided whether caloric be a material agent, or the mere effect of motion among the particles of ponderable matter, it becomes necessary to examine the evidence on which these opposite views have been founded.

Among the most enlightened nations of antiquity, elementary fire was regarded not only as the most refined and spiritual of all the elements, but as a universal and self active principle, which they considered as identical with exist

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ence or being. It has been amply proved by Bryant, Calmet, and other learned etymologists, that the Greek esi, and the Latin esse, to be, like our words essence and essential, were derived from the Hebrew & Esh or Es, the fire; and that Vesta, the goddess of that element, had her name from the Chaldee nex Eshta or Esta. They have also shown that the word D Am denoted both heat and existence, among the early Egyptians; who, believing it to be the cause of motion and organization throughout nature, inscribed it on the great door of one of their temples.

We are further informed by the learned and philosophical Parkhurst, that the sacred mystical letters In Ie, which were inscribed over the door of the temple at Delphi, dedicated to Apollo, (who was a mythological personation of the sun or solar fire,) were taken from the Hebrew Yeh or Yah, signifying existence or being. Nor is it unworthy of notice, that the Greek #ʊp fire, was derived from the Hebrew 1 pur, to break, dissolve, and separate; actions which clearly imply mechanical and material agency. So much for the primitive meaning of words employed by the ancients to represent the essential nature of what is called heat, but which I shall generally denominate caloric, for the purpose of distinguishing the cause from the mere sensation of heat. Let us now examine the views which have been entertained by the moderns on this important subject.

In the Novum Organum, and in his Treatise entitled De Forma Calidi, it was maintained by Lord Bacon, (whose opinion has been adopted by a majority of philosophers since his day,) that the very essence of heat is motion and nothing else. In accordance with this doctrine, Sir H. Davy observes, in his Chemical Philosophy, that “ the cause of heat is motion, and the laws of its communication are precisely the same as the laws of the communication of motion." But in the Treatise on Life and Death, as also in his Natural History, Bacon maintains that "there is in every tangible body, a spirit or body pneumatical, which fills the pores of all gross bodies:-that it is not some virtue, or action, or trifle, but a real and quantitative substance, though rare, invisible, and without weight." Moreover, that this spirit or body pneumatical, was only another name for what Hippocrates and other Greek authors called Depμov heat, (and sometimes TvEvμa spirit,)is equally manifest from the fact, that Bacon represents it as the cause of evaporation, and of many other effects which are predicable of caloric alone. And Sir Humphrey Davy observes in his Agricultural Chemistry, that "whatever theory we adopt, it is certain that there is matter moving in space between us and the heavenly bodies, capable of communicating heat." It is therefore evident, that neither of these distinguished men can be fairly ranked as advocates of the immaterial

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theory; and that, in reality, they had no fixed or settled opinions on the subject.

The authority of Sir Isaac Newton has been often cited in support of the doctrine, that caloric is not a material substance. But it is worthy of special notice, that in all the latest works of that great man on physical science, he maintains the existence of what he calls" an exceedingly subtile and elastic æthereal substance, which is diffused through all places, fills the pores of gross bodies, and forms a large constituent of their bulk or volume." In a letter addressed to the celebrated Boyle in 1678, the object of which was to explain his views of the æther, he represents it as "the cause of cohesion, capillary attraction, and of the force by which menstruums pervade and dissolve solid bodies." He adds in another sentence, "I conceive the atmosphere to be composed of the particles of all sorts of bodies of which the earth consists, separated and kept at a distance from one another by the same active principle.

* The above views were still further expanded in a scholium at the close of the second edition of the Principia, published in 1713; and in the form of queries, they were reiterated at the close of the Optics, published in 1717. In both of these great works, he represents the æther as the cause of gravity, cohesion, capillary attraction, solution, elasticity, the emission, reflexion, refraction, and inflexion of light. He also maintained that the æther is the cause of animal motion. Yet he observes, that he knows not what the æther is; and that" we have not that sufficiency of experiments which are requisite to an accurate determination of the laws by which this subtile spirit operates."

But if the æther be the cause of solution, and of the elastic force of the atmosphere, it is manifestly identical with caloric. It is true that in

the fifth query, towards the close of the Optics, Newton represents heat as consisting in a vibratory motion among the particles of bodies,-and that the whole theory of the Principia was founded on the hypothesis that space is a vacuum; which is certainly at variance with the foregoing views of the æther. It is also inconsistent with his doctrine of light, which he regarded as a material substance, perpetually flowing from the sun and fixed stars through space. But that caloric does not consist in mere motion or vibration among the particles of ponderable matter, would appear from the following considerations:—

1. That it may be added to and subtracted from other bodies, and measured with mathematical precision, as all good thermometers de

monstrate:

2. That it augments the volume of bodies, which are again reduced in size by its abstraction :

But if Newton had traced the word æther to its primitive roots, he would have found that it was a Greek noun, which was derived from two Phoenician or Hebrew words, Ath or Aith the sun, and Ur fire, meaning the solar fire,—a discovery which probably would have modified all his physical investigations, and have given a totally new aspect to the whole circle of the Sciences. The truth is, that a complete Etymological Dictionary would sweep away innumerable misconceptions, errors, and metaphysical subtleties, which have gradually arisen from the revolutions in language, and the adoption of words, the primitive meaning of which has not been understood.