three circles of meteoric action, as noticed, a like species of connexion appears to subsist between the appearance or occurrence of certain meteors, and the changes which take place in the meteoric action of each of these circles. As, for instance, it is only at the periods of the great changes which take place in the annual circle connected with those of the seasons, whether at the equinoxes, or during the winter progression or transition quarters,-that either the larger class of globular meteors make their appearance in the middle or lower latitudes, or the aurora borealis in those lying further north. And, of which it may be further observed, that, owing to their being the result of a more powerful action, as that a greater depth of the atmosphere is affected thereby than is the case on ordinary occasions, these meteors are usually the precursors of some of the most violent storms of the year. Thunder and its accessory phenomena, on the contrary, being usually the effects-during spring and summer-of the changes which take place in the lunar action; and with which the changes in the annual circle have no part. Dew and Fog, as is known,

* Fog, or mist, as is known, is the first stage of the meteor in which rain has its source; and beyond which, when either of the contributing actions-electric or magnetic-which are esteemed necessary to the production of the rain-cloud, do not concur to the required extent, it does not progress. And as being illustrative that this is the case, it may be observed that though at Lima

being more particularly connected with the changes that take place in the diurnal circle.

But to revert to the aurora borealis,—from its being a meteor which, as is known, has long excited the attention of the scientific world; and that, as I conceive, a conclusive proof of the correctness of the principles assumed by our theory is to be derived from it; I have thought it right to notice it in this place. Thus, as refers to the assumed connexion which subsists between the axes of the opposite actions of the sun in the atmosphere, as between those of its meteors and currents, in traversing each other at right angles. And the assumption, that it is on

the occurrence of rain is so unusual; fog, or mist, on the contrary, during great part of the year, is of almost daily occurrence. And further, that in the polar skies during summer, this the frequency of fog, and absence of rain is likewise observable :-thence, agreeable to this double testimony, we have proved in the clearest manner, the correctness of the principle assumed, in reference to the rain-cloud. As where at one extreme of the scale of these actions, in the climate of Lima, magnetic action is so disproportioned to its opposite in reference to the production of rain, we find the meteor in which it has its source, though frequently commenced, cannot, in consequence, progress beyond this its first stage :-and that at its opposite extreme in the polar skies, from a similar disparity in electric action, as contrasted with magnetic, the result in this respect is still the same. And, consequently, as refers to the central regions of this meteoric scale,-in either hemisphere, or where these opposite actions in the atmosphere are the most equally blended,-why it is that, in these their temperate zones, the occurrence of rain is the most frequent.

the axis of the weaker or subordinate action of the sun in the middle or superior region of the atmosphere, that the meteors form which are induced by the inverse or concentric action of these forces in those regions in which rain and its accessories have their source; as that the direction of the axis of the opposite or dominant action of the sun, is that of the currents in the inferior region which those meteors induce. Under this point of view, esteeming the aurora borealis to be of the same species of meteoric action as that in which thunder and its accessories have their source, i. e. the inverse or concentric action of the electric and magnetic forces in the region where it occurs: but with this difference, that as electricity is esteemed to be the ground of the meteor, as stated, in which thunder has its source,―magnetic action, on the contrary, is esteemed the base of the meteor in which the aurora has its source; i. e. that, in the conjoint action of the electric and magnetic forces which has the preponderance. And as this, according to the principles assumed would, if correct, cause that the axis of the aurora should traverse the line described by the magnetic meridian; we shall find that in every instance of its appearance such is the case. The angle which the axis of the aurora forms with the magnetic meridian-varying with the distance from the pole-being more completely a travers or at right angles with it in the higher latitudes; and, si

milar to the currents, deviating more or less from this as it approaches farther south:-the storms which succeed, as should be the case, taking an opposite direction. It may be further observed of the aurora, that, esteeming its coruscations to be of the same nature as the lightnings projected from the thunder-cloud, and that the direction of the latter is to the earth, or inferior region of the atmosphere, where, at the time, electricity is still in an idio-electric state and which direction of lightning to the inferior region, is probably an effect of the electric attraction which, as is known, exists between bodies in opposite states of electricity. Thus, as magnetism is assumed to be the predominant action in the production of the aurora; and that the lightning or corruscations it projects, instead of taking the direction of the earth, ascend in the opposite, or to the zenith-may not the cause of this be that, as the base or ground of the meteor which originates the aurora is magnetic, and that, as in the instance of the thunder-cloud,—as magnetism exists in the superior region of the atmosphere above it, similar to electricity, in the latter case, in the inferior region, in what may be denominated an idio-magnetic, or different state from what it does in the meteor beneath; that this the direction of the corruscations of the aurora may not be an effect of the attraction which, as in the former case, may exist between bodies in opposite states of magnetism?

CHAP. XVII.

Further Proof of Principles, in reference to the assumed Influence of Magnetic Action, derived from the sudden and total Change of the Seasons at the Periods of the Equinoxes, on the opposite Sides of the Peninsula of India.

AND, as being esteemed further illustrative of the important influence exercised by magnetic action in particular localities on the seasons and weather,— assuming it to be the cause:-in addition to the instance noticed in the climate of Lima, may be cited the total change from summer to winter, or from drought to rain, which at the periods of the equinoxes takes place on the opposite shores of the Peninsula of India, separated as they are by the lofty chain of mountains which traverses its centre, i. e. those of Malabar and Coromandel. A change so sudden and remarkable as to have not only attracted the attention, but excited the astonishment of naturalists; and of which the following account, copied from the first volume of Raynal's celebrated work on the Commerce of both the Indies, "L'Indostan n'est may serve to convey an idea:

que le pays renfermé entre l'Indus et le Gange, deux fleuves célèbres qui vont se jetter dans les mers