and tangible forms; consequently, that it is the self-active and universal essence on which all the manifestations of being or existence depend.*

Yet we are told that caloric is not a material substance, because it is imponderable. It is evident, however, that whatever the cause of gravity may be, it must be imponderable without gravity; otherwise we must explain gravity by itself, which would be absurd. The truth is, that when reduced to a state of ultimate diffusion, all matter is imponderable, as in the form of the electric spark, flame, &c. And if caloric were "motion and nothing else," as maintained by Bacon and other philosophers, it would follow that the prime mover in a steam engine, and throughout all nature, is motion,—a proposition which involves the glaring absurdity of explaining motion by itself.

But without plunging further into the profound abyss of chaos, or practical non-existence that would follow the entire extinction of the organizing principle, it is the legitimate province of science to ascertain how it produces all the phenomena of nature in accordance with the invariable laws of supreme intelligence. Nor is it possible to predict the results which would flow from a searching method of analyzing facts. We often mistake our own inattention

* And if the particles of all bodies be surrounded by a self-active principle, there can be no such thing as absolute inertia in nature.

and indolence, or the mystical inventions of fanciful theorists for impenetrable obscurities, that would vanish before a bold and determined spirit of inquiry. Could the veil be drawn aside which conceals from our inspection the whole mechanism of the universe, nothing, perhaps, would so much excite our astonishment as its simplicity.

From a careful review of the foregoing Chapters, the following conclusions may be deduced: 1. That cohesion, chemical affinity, and capillary attraction, are modifications of that uni

In opposition to this view of the subject, we are informed by Dr. Arnott, that "the greater part of the phenomena of nature may be referred to four elementary truths, viz. atom, attraction, repulsion, and inertia." He observes, that " inertia expresses the fact, that atoms, as regards motion, have a stubbornness about them, which tends always to keep them in their existing state, whatever it may be." (Elements of Physics, Vol. I. page 1 and 2.) In what way atoms have been endowed with this imaginary property has not been explained; nor does Dr. Arnott assign the cause of attraction. Until this is done, let no man flatter the world, that even the foundation of physical science has been established on the solid rock of fixed principles.

If it be true that caloric is the physical cause of attraction as well as repulsion, and that cohesion and gravity are modifications of the same power, it must be a primum mobile: it therefore becomes the business of philosophy to investigate the mode of its operation in maintaining all the molecular and aggregate movements of nature.

The connexion of caloric with the phenomena of motion has been virtually recognized by all those philosophers who have regarded heat and motion as identical. But it is obvious that there can be no motion without an agent; consequently, that they have confounded the effect with its cause.

versal force by which planets and all other bodies are held together:

2. That the particles of all bodies are surrounded by, and intimately combined with an exceedingly subtile, active, and mobile principle, which in certain proportions holds them together, but in larger proportions separates or decomposes them :

3. That the prevalent theory of physics which ascribes the phenomena of attraction to the inherent, or immaterial properties of ponderable matter, is fallacious, and wholly unsupported by evidence:

4. That there is no such thing as a perfect vacuum in nature; neither in the pores of bodies, nor in those widely extended pores of the universe, termed the planetary spaces:

5. That the inertia of matter is a philosophical fiction, because there is nothing quiescent in nature, or which possesses the power of not acting-neither in the starry heavens, nor in the frame of the earth. The sun revolves on his axis, and planets around the sun. The air, the ocean, and the solid ground are for ever in motion. The molecules of plants and animals are in a state of rapid circulation and change. Yea, the invisible atoms of inorganic matter are in a state of perpetual oscillation and transformation :

6. That the "unknown hypothetical æther' of Sir I. Newton is identical with a true phy

sical agent, the properties of which may be ascertained by the various mechanical, chemical, and physiological effects it produces that it causes the aggregation and chemical union of bodies, whether simple or compound, by virtue of its attraction for ponderable matter, and not by pressure, as supposed by Newton; while it causes evaporation, gasefaction, explosion, with all the separations and expansions of matter by virtue of its idio-repulsive power :

7. That if the earth were wholly deprived of caloric, it would become a stupid mass of inert and chaotic matter, without form, and void of all power of attraction and repulsion, of solidity, fluidity, &c.

8. That the total extinction of the solar fluid, (if such a thing were possible,) would mark the reign of everlasting stillness and death--that the same æthereal principle which lights up the universe with radiant glory, directs the planets through their orbits, and preserves them in a state of perpetual motion, circulation, and renovation: finally, that caloric is the first of second

causes.

BOOK III.

CHAPTER I.

Electricity.

"Nature will not deliver her oracles to the crowd, nor by sound of trumpet. We must open our minds to her in solitude, with the simplicity of children, and look earnestly in her face for a reply."

WALTER SAVAGE LANDOR.

THE grand requisite to a right understanding of nature, is to watch attentively all the changes that mark her progress, and the various circumstances by which they are attended. Perhaps there is not a more striking characteristic of the present age, than the vast amount of industry and talent that are devoted to the cultivation of separate branches of science, which cannot be understood but as connected parts of one harmonious system. The leading object of all science is to reduce a multitude of phenomena to some universal principle, or general law, which pervades the entire constitution of matter. But how is it possible to arrive at universal facts or fundamental laws, without regarding nature as a whole?