er in the middle latitudes.

Hence we infer, that the

caloric of vapor, when greatly accumulated, is given out rapidly, in the form of electricity, on approaching a colder mass of vapor, which is negatively charged with caloric."

But it may, in this connection, be asked, what causes rain, when lightning is not visible. The caloric is given out gradually, and, in such a volume that it is latent. This is either done by the vicinity of cold and warm masses of vapor, or the attraction of mountainous ridges, or of the minus earth.

If this be true, we can see, at once, the reason why, upon the great desert of Zahara, where there are no mountains, and where the earth is almost always plus, it rarely, if ever, rains. The earth, being plus, and imparting caloric to the masses of vapor, as they float over it, rarefies them, and makes them float higher, rather than aids in their condensation. It would be utterly impossible, therefore, for it to rain oftener upon that desert.

The same cause dissipates all appearances of rain in certain sections during the prevalence of a drouth, so that showers will pass round day after day, each side of them, and seem to shun them. The earth has, in those sections, become plus and rarefies the clouds, as they pass by, floats them higher, and prevents condensation. As a general occurrence, such spots are encroached upon gradually by showers, until they are, at length, made minus, and then they are visited by the refreshing rain.

Could a large tower be erected, some one or two thousand feet high, in the very centre of the great desert of Zahara, and could its top be kept filled with ice, it would be the cause of the perpetual nimbification of clouds, by its abstraction of their caloric.The consequence would be that it would be visited with frequent and vivifying showers.

The sun is the great fountain of light. Were it, however, extinguished, as in Byron's poetic dream on darkness, there would be neither heat nor electricity, and on the other hand, were there no heat nor electricity, there could be no light; for light is necessarily produced by the heat, which is indispensably requisite to render substances combustible, and, without which, they would not ignite, nor become combustible, nor luminous at all. They are inseparable from each other, and from electricity, and if you destroy the existence of the one, by the same process, you destroy the existence of all.

The fact is, the sun, which sends forth its streams of light and heat, is the great fountain of electricity -the great galvanic battery of the solar system.Could it be stripped, at once, of those splendors, which sweep incessantly over the vast domain of its dependent worlds, and be left a dark, cold, opaque body, what think you, would be the consequence? Why, in less than twenty-four hours, yea, in less than twelve hours, this globe would become a solid mass of ice, from surface to centre, as well as every other body of the solar system. The very atmosphere would be

congealed into an iceberg. The heart of nature would cease to beat. The pulse of nature would stand still. The powers of nature would all be palsied, chilled, and frozen to death. In such a supposed contingency, the orbs, if they moved at all, would wander, cheerless, black and without order, through the vast expanse of desolation, dashing madly against each other, in their blind and ungoverned

career.

Or else, as is most probable in such a contingency, all motion would be stagnated, and every energy, every muscle, every nerve of the universe would be withered, stiffened, clothed with the rigidity of death. All sound would die away upon the palpable blackness of chaos. No elastic medium would convey the tones of harmony by its vibrations. All nature would be dumb.

While thinking upon this subject, I have permitted imagination, sometimes, to have unfettered sway, and to sketch the gloomy picture of the reality of such a supposition. In doing so, no description of the scene which I could paint, seemed so graphic, as the language of Byron's poetic dream on darkness, when

แ

66- -The world was void.

The populous and powerful was a lump,
"Seasonless, herbless, treeless, manless, lifeless,
"A lump of death-a chaos of hard clay.

"The rivers, lakes and oceans all stood still,

And nothing stirred within their silent depths.

Ships sailorless, lay rotting on the sea,

"And their masts fell down piece meal

"As they dropped, they slept upon the abyss without a surge. "The waves were dead. The tides were in their graves.

"The moon, their mistress, had expired before,

"The winds were withered in the stagnant air,

"And the clouds perished. Darkness had no need

Of aid from them-SHE WAS THE UNIVERSE."

This description, or a description like this, though almost horrid enough to make the blood run chill, would be no fiction. Should the light and caloric of the sun be abstracted from the universe, there would be no electricity. It would, with the rapidity of a flash, complete its circuit, and perish with its cause. It could be no longer excited by friction. No galvanic arrangement of metalic plates, could produce it.— And then, motion would cease. All life would in

stantly become extinct, and darkness and death would reign triumphant and universal.

LECTURE IX.

THE CAUSES OF MAGNETIC ATTRACTION, THE AURORE, GRAVITATION, COHESION, AND THE MOTION OF PLANETS DEMONSTRATED BY A VARIETY OF ARGUMENTS TO BE ELECTRIC AND IDENTICAL.

In view of the facts and arguments, which have already been submitted to the reader, we shall now consider it a conceded point, that we have proven the identity between solar light, caloric and electricity. To test still farther the correctness of the principles advocated, we will proceed to account, if possible, for certain mysterious and hitherto inscrutable phenomena, which can be satisfactorily accounted for, if our positions be, at all, tenable.

There have, for ages, been certain vague and indefinite ideas, floating in the public mind, respecting the causes of magnetic attraction. While some have thought, that there was a certain incomprehensible control over the needle of the compass exerted by the north pole star, others have approached somewhat nearer to scientific accuracy, by ascribing this controling influence to terrestrial magnetism. But how terrestrial magnetism is produced, and by what laws it is governed, the latter class have been about as much in the dark as the former. But, if the positions we have assumed be true-if solar light and