And besides the falling of these from the cloud, there is described to have been a fall of sand; seen by keepers of cattle near Cozone, together with the falling of what appeared like squibs; and which proved afterwards to be stones, of the sort just described, weighing two or three ounces :-and some only a quarter of an ounce.

Amongst other stones that fell; was one weighing two pounds, and two ounces; which was also an oblong parallelopiped, with blunted angles, (as they are called, but which I think meant plainly prismatical terminations, and are said to have been about an inch in height;) and this was most remarkable for having, a small circle, or sort of belt round it, in one part; wherein the black crust appeared more smooth ; and shining like glass; as if that part had suffered a greater degree of heat than the rest.

Another, also, was no less remarkable, for having many rounded cavities on its surface: as if the stone had been struck with small balls, whilst it was forming; and before it was hardened; which left their impressions.-And some appearances, of the same kind, were found on one of the four surfaces of another stone, in the possession of Soldani.

On minute examination, the Professor found the stones were composed of blackish crystals, of different kinds; with metallic or pyritical spots, all united together by a kind of consolidated ashes.-And, on polishing them, they appeared to have a ground of a dark ash colour; intermixed with cubical blackish crystals, and shining pyritical specks, of a silver and gold colour.

The conclusion which Professor Soldani evidently forms, is; that the stones were generated in the air, by a combination of

mineral substances, which had risen somewhere or other, AS EXHALATIONS, from the earth: but, as he seems to think, not from Vesuvius.

The names of many persons, besides those already referred to, are mentioned; who were eye witnesses to the fall of the stones. And several depositions were made, in a regular juridical manner, to ascertain the truth of the facts.

The space of ground, within which the stones fell, was from three to four miles.

The falling of them, was the very day after the great eruption of Vesuvius.

And the distance of the place, from Vesuvius, could not be less than two hundred miles, and seems to have been more.

Vesuvius is situated to the south of the spot and the cloud came from the north; about thirteen, or at most eighteen hours, after the eruption.

Now, putting all these circumstances together, I cannot but venture to form a conclusion, somewhat different from Professor Soldani's; though perfectly agreeing with his general principles.

From a course of observations, and inquiries, which I have been led to pursue, for a great many years: tending to elucidate the history of extraneous fossils, and of the deluge; I have long been convinced, that stones in general, and strata of rocks, of all kinds, have been formed by two very different operations of those elements, which the wisdom, and omnipotent hand of God, has ordained, and created.

The one, by means of fire:-and the other, by means of

water.

And, of each sort, there are two subdivisions.

Of the stones, and rocks, formed by fire;-there are some, (besides lavas,) whose component parts, having been previously fused, and in a melted state, did merely cool, and harden gradually.

And there are others; whose component parts, having been fused, and in a melted state, and having so become completely liquid; did instantly, by the operation of the powers of attraction, become crystallized.

And, in like manner; of stones, and of strata of rocks, formed by means of water;—there are some, which having had their component parts brought together, ir a fluid state; did then merely become gradually settled; and by the power of attraction, and the mixture of crystalline particles, were hardened by degrees.

And there are others: which, having had their component parts, in like manner, brought together by water, did yet, on account of the peculiar nature, and more powerful attraction of those parts, instantly crystallize.

And both of stones, and of strata of rocks, formed by fire; and of stones, and of strata of rocks formed by means of water; there are some such, as have been slowly consolidated by the first kind of operation; namely by the gradual cooling or settling of the substances; which yet do contain imbedded in them, crystals formed by the latter kind of operation,

Instances of which, we seem to have, in some granites, on the one hand;—and in some sorts of limestones on the other.

To this I must add also; that there appear further, to have been some stones formed by a sort of precipitation: much in the

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same manner as Grew describes * the kernels, and stones of fruit to have been hardened.

And I have met with many instances, wherein it appears unquestionably, that all these kind of processes in nature are going on continually: and that extraneous substances are actually inclosed, and continually inclosing, which could not be antediluvian; but must have been recent.

To these short premises, I must beg leave to add; that in two papers formerly printed in the Philosophical Transactions, I endeavoured, by some very remarkable instances, to prove, that iron, wherever it comes into combination with any substances that are tending to consolidation, hastens the process exceedingly ;—and also renders the hardness of the body much greater.

And I have also endeavoured, elsewhere, to shew, in consequence of conclusions deduced from experiments of the most unquestionable authority, that air, in its various shapes and modifications, is indeed itself the great consolidating fluid, out of which solid bodies are composed; and by means of which the various attractions take place, which form all the hard bodies, and visible substances upon earth.

From all these premises then, it was impossible for me not to be led to conclude; that we have, in this august phænomenon of the fall of stones from the clouds, in Tuscany, an obvious proof, as it were before our eyes, of the combined operation of those very powers, and processes, to which I have been alluding.

It is well known; that pyrites, which are composed of iron,

In his Anatomy of Plants, p. 41-184. + Vol. LXIII. p. 241-and Vol. LXIX. p. 35. In the Morsels of Criticism, p. 103.

and sulphur, and other adventitious matter, when laid in heaps, and moistened, will take fire.

It is also well known, that a mixture of pyrites of almost any kind, beaten small, and mixed with iron filings and water, when buried in the ground will take fire; and produce a sort of artificial volcano. And, surely then, wherever a vast quantity of such kind of matter should at any time become mixed together, as flying dust, or ashes; and be by any means condensed together, or compressed, the same effect might be produced, even in the atmosphere and air.

Instead, therefore, of having recourse to the supposition, of the cloud in Tuscany having been produced by any other kind of exhalations from the earth; we may venture to believe, that an immense cloud of ashes, mixed with pyritical dust, and with numerous particles of iron, having been projected from Vesuvius to a most prodigious height, became afterwards condensed in its descent;-took fire, both of itself, as well as by means of the electric fluid it contained ;-produced many explosions ;-melted the pyritical, and metallic, and argillaceous particles, of which the ashes were composed ;—and, by this means, had a sudden crystallization, and consolidation of those particles taken place, which formed the stones of various sizes, that fell to the ground: but did not harden the clayey ashes so rapidly as the metallic particles crystallized; and, therefore, gave an opportunity for impressions to be made on the surfaces of some of the stones, as they fell, by means of the impinging of the others.

Nor does it appear to me, to be any solid objection to this conclusion, either that Vesuvius was so far distant; or that the cloud came from the north.

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