In our second volume, to which we beg leave to refer, we have unfolded our own sentiments rela tive to the very problematical source of these occa sional visitants of our planet ; and as these views still appear to us less exceptionable than any others which have been submitted to our notice, we shall glance at some of the latter with all suitable brevity.
The opinion of the Parisian Academicians, who, in the middle of the last century, maintained that the stones in question merely resulted from a stroke of lightning on the spot in which they were found, will not, in the present clay, hear a moment's examination ; for we have seen, that thunder and lightning do not necessarily accompany the fall of meteorites; and that these last differ from all the solid substances on the face of the globe. We will not deny, that lightning may tear up the soil, and convert it into a solid mass; but we have no proof of its competency to project masses, so formed, into an indefinite height in the at mosphere, nor to generate thousands of hard stones in fine cloudless weather.
The supposition that such concretions have been driven off from some of our volcanos, is scarcely less tenable ; for the compound lavas of burning mountains are never found remote from the scene of their forma tion; and none of them present the aspect and charac ters of the bodies which we have described. Besides, most of the stony showers on record are represented as occurring when no remarkable volcanic eruption was known to have taken place. The ashes of a violent eruption have frequently, from their levity, been waft ed to a considerable distance ; but we are altogether unacquainted with any projectile force which can dart solid and heavy masses hundreds of leagues, through such a dense medium as the atmosphere. Mr. King, indeed, is inclined to believe, that an immense cloud of ashes. pyritical dust, and particles of iron, forcibly propelled from Vesuvius to a very great height, be came condensed in its fall, took fire from its motion in the air, and its electrical elements, and thus gave birth to the Siena stones. But he does not thus account for the presence of nickel in their composition, nor for the other obvious discrepancies between volcanic ashes and meteoric stones. In order to explain the direction of the cloud which proceeded from the north, he has re course to the supposition, that it was at first driven, in its course, to the northward of Siena, and afterwards urged hack by a contrary current of wind. But the
cloud itself, and its destinies, are alike gratuitous: and it is much more conformable to what we know of pa rallel cases, to conceive that the Siena phenomenon would have occurred at the time, and in the manner in which it did occur, although Vesuvius had remained in a state of perfect quiescence.
In the boldness of his speculations, M. Bory de Saint Vincent takes a still wider flight, and sends forth his meteorites from immense depths, in some early stage of the earth's existence, when ignivomous mountains, as he pompously denominates them, were endowed with propelling forces adequate to the dispersion of matter into the regions of space, in which they were constrained, for ages, to obey the compound laws of impulse and gravitation, until, in the progress of time, their spiral revolutions terminated on the surface of their native planet. Before, however, we can tamely acquiesce in the terms of such an extravagant hy pothesis, we may be permitted to call for the evidence of the existence of those ancient and wonder-working volcanos, which could communicate planetary motion to chips of rock, without up-heaving the rocks them selves.
The sagacious Troili, too, in his endeavours to ac count for a fact which he has so triumphantly proved, labours to convince his readers that the Albereto stone must have been torn from the bowels of the earth, and projected to a great height by the powerful agency of subterraneous conflagration; and these conflagrations he conjures up at pleasure to suit his purpose. On such a supposition, however, the burs•.1g of stones from the surface of the earth, and their ascent into the air, should be as frequently seen as their fall to the ground, and some of the profound openings and fissures occasioned by their violent passage through the strata, ought, before now, to have been observed; for we ::re not entitled to presume that they were all effected in the recesses of forests, or closed again after the stones had made their escape. Again, an expansive force commensurate to the conditions of the hypothesis, would occasion wide and ruinous disorder, to hich could scarcely fail to be observed in every inhabited country.