tag="{http://www.w3.org/1999/xhtml}a">[1]Extract from a letter from Professor Henry.

MECHANICAL THEORY OF STORMS.

SECTION FIRST.

PRESENT STATE OF METEOROLOGY.

The present state of the science of which we are about to treat, cannot be better defined than in the words of the celebrated Humboldt, who has devoted a long life to the investigation of this department of Physics. He says: “The processes of the absorption of light, the liberation of heat, and the variations in the elastic and electric tension, and in the hygrometric condition of the vast aërial ocean, are all so intimately connected together, that each individual meteorological process is modified by the action of all the others. The complicated nature of these disturbing causes, increases the difficulty of giving a full explanation of these involved meteorological phenomena; and likewise limits, or wholly precludes the possibility of that predetermination of atmospheric changes, which would be so important for horticulture, agriculture, and navigation, no less than for the comfort and enjoyment of life. Those who place the value of meteorology in this problematic species of prediction, rather than in the knowledge of the phenomena themselves, are firmly convinced that this branch of science, on account of which so many expeditions to distant mountainous regions have been undertaken, has not made any very considerable progress for centuries past. The confidence which they refuse to the physicist they yield to changes of the moon, and to certain days marked in the calender by the superstition of a by-gone age.”

The charge thus skilfully repelled, contains, however, much truth; there has been no adequate return of the vast amount of labor and expense thus far devoted to this branch of knowledge. And it is not wonderful that the popular mind should expect a result which is so much in accordance with the wants of mankind. Who is there whose happiness, and health, and comfort, and safety, and prosperity, may not be more or less affected by reducing to law, the apparently irregular fluctuations of the weather, and the predetermination of the storm? To do this would be the crowning triumph of the age; and the present theory has pioneered the way for its speedy accomplishment.

ORIGINAL CONDITION OF THE EARTH.

That the present order of things had a beginning, is taught by every analogy around us, and as we have the glaring fact forced upon us, that our globe has experienced a far higher temperature on its surface than obtains at present, and moreover, as it is demonstrated beyond a cavil, that the interior is now of far higher temperature than is due to solar radiation, we are justified in concluding, not only that the condition of the interior of our globe is that of fusion, but that its original temperature was far higher than at present; so that the inference is allowable that there has been a time when the whole globe was perhaps in this state. But why should we stop here? There are three states of matter, the solid, the fluid, and the gaseous; and with this passing glance at the question, we will jump at once to the theory of La Place,—that not only our own globe, but the whole solar system, has been once in the nebulous state.

In justice to himself, the author ought to remark, that he had reasoned his way up to this starting point, before even the name of La Place had reached his ears. He makes the remark in order to disclaim any desire to appropriate that which belongs to another; as he may innocently speak of things hereafter, the idea of which has occurred to others. It is not his intention here to say a word pro or con on the nebular hypothesis; it is sufficient to allude to the facts, that the direction of rotation and of revolution is the same for all the planets and satellites of our system; and that the planes on which these motions are performed, are nearly coincident. That this concordance is due to one common cause, no one acquainted with the theory of probabilities will pretend to deny.

GREAT OBJECT OF LA PLACE.

The science of Astronomy occupies a pre-eminent rank in the physical circle, not only on account of that dignity conferred upon it in the most remote antiquity, or as being the grand starting point—the earliest born of science—from whence we must contemplate the visible creation, if we would reduce its numerous details into one harmonious whole; but also on account of its practical fruits, of the value of which modern commerce is an instance. Accordingly we will glance at its past history. In the earliest ages there was no doubt a rational view entertained of the movements of the planets in space. From the Chaldeans to the Arabs, a belief prevailed, that space was filled with a pure ethereal fluid, whose existence probably did not rest on any more solid foundation than analogy or tradition. One hundred years after Copernicus had given to the world the true arrangements of our planetary system, Descartes advanced his theory of vortices in the ethereal medium, in which the planets were borne in orbits around the sun, and the satellites around their primaries. This idea retained its ground with various additions, until the Geometry of Newton reconciled the laws of Kepler with the existence of a power pertaining to matter, varying inversely as the squares of the distances, to which power he showed the weight of terrestrial bodies was owing, and also the revolution of the moon about the earth. Since Newton’s day, those deviations from the strict wording of Kepler’s laws, have been referred to the same law, and the avowed object of the author of the “Mechanique Celeste,” was to bring all the great phenomena of nature within the grasp of analysis, by referring them to one single principle, and one simple law. And in his Introduction to the Theory of the Moon, he remarks: “Hence it incontestibly follows, that the law of gravitation is the sole cause of the lunar inequalities.”

BESSEL’S OPINION.

However beautiful the conception, it must be admitted that in its à priori aspect, it was not in accordance with human experience and analogy to anticipate a successful issue. In nature law re-acts upon law, and change induces change, through an almost endless chain of consequences; and it might be asked, why a simple law of matter should thus be exempt