the descent of water from the atmosphere in the form of drops of considerable size. By this circumstance it is distinguished from dew and from fog. In the former the drops are so small that they are quite invisible; in the latter, although their size be larger, they seem to have very little more specific gravity than the atmosphere itself, and may therefore be reckoned hollow spherules rather than drops. This subject will be found fully discussed in the articles on Meteorology, Physical Geography, and Weather.

Preternatural Rains. We have numerous accounts, in the historians of our own as well as other countries, of preternatural rains; such as the raining of stones, of dust, of blood, nay, even of living animals, as young frogs, and the like. We cannot doubt the truth of what authors of veracity and credit relate to us of this sort, nor can we suppose that the falling of stones and dust never happened; the whole mistake consists in supposing them to have fallen from the clouds. But as to the blood and frogs, it is very certain that they never fell at all, and the opinion to the contrary has been produced by a mere deception of sight. Men are extremely fond of the marvellous in their relations; but the judicious reader must examine strictly whatever is reported of this kind, and not suffer himself to be deceived.

There are two natural methods by which quantities of stones and of dust may fall in certain places, without their having been generated in the clouds or descended as rain. The one is by means of hurricanes; the wind which we frequently see tearing off the tiles of houses, and carrying them to considerable distances, being equally capable of raising a quantity of stones, and dropping them again at some distant place. But the other, which is much the most powerful, and probably the most usual way, is by the eruptions of volcanoes and burning mountains tossing up, as they frequently do, a vast quantity of stones, ashes, and cinders, to an immense height in the air; and these, being hurried away by the hurricanes and impetuous winds which usually accompany such eruptions, and being in themselves much lighter than common stones, from being half calcined, may thus be easily carried to vast distances, and there falling in places where the inhabitants know nothing of the occasion, cannot but be supposed by the vulgar to fall on them from the clouds. It is well known, that, in the great eruptions of Etna and Vesuvius, showers of ashes, dust, and small cinders, have been seen to obscure the air, overspread the surface of the sea for a great way, and cover the decks of ships; and this at such a distance, that it might appear scarcely conceivable they should have been carried so far; and probably, if the accounts of all the showers of these substances mentioned by authors were collected, they would all be ascertained to have fallen within such distances of volcanoes, whilst, if compared as to the time of their falling, they would be found to correspond in that also with the eruptions of those mountains. We have known instances of the ashes from Vesuvius having been carried thirty, nay, forty leagues; and peculiar accidents may have carried them still farther. It is not to be supposed that these showers of stones and dust fall continuously in the manner of showers of rain, or that the fragments or pieces are as frequent as drops of water. It is sufficient that a number of stones, or a quantity of dust, fall at once on a place, where the inhabitants can have no knowledge of the point whence they came, and the vulgar will not doubt their dropping from the clouds. Nay, in the canton of Berne, in Switzerland, the inhabitants accounted it a miracle that it rained earth and sulphur upon them at a time when a small volcano terrified them; and even whilst the wind was so boisterous, and hurricanes so frequent, that they saw almost every moment the dust, sand, and little stones torn up from the surface of the earth in whirlwinds, and carried to a considerable height in the air, they never considered that both the sulphur thrown up by the volcano, and the dust, sand, and stones carried from their feet, must soon afterwards fall somewhere. It is very certain that in some of the terrible storms of hail, where the hailstones have been several inches in circumference, there have been found, on breaking them, what people called stones in their middle; but these observers need only to wait the dissolving of one of these hailstones, to see the stone in its centre also disunite, it being formed merely of the particles of loose earthly matter, which the water, exhaled by the sun's heat, had taken up with it in extremely small molecules, and this serving to give an opaque hue to the inner part of the congelation, to which the freezing of the water alone gave the apparent hardness of stone.

The raining of blood has ever been accounted a more terrible sight and a more fatal omen than the other preternatural rains already mentioned. It is very certain that nature forms blood nowhere but in the vessels of animals, and therefore showers of it from the clouds are by no means to be credited. Those who suppose that what people took for blood has actually been seen falling through the air, have had recourse for its origin to flying insects, and suppose it to be the eggs or dung of certain butterflies discharged as they were high up in the air. But this seems to be a very wild conjecture, as we know of no butterfly the excrements or eggs of which are of such a colour, or its abode so high in the air, or its flocks so numerous, as to be the occasion of such a phenomenon.

It is most probable that these bloody waters were never seen falling; but that people, seeing the standing waters blood-coloured, were assured, from their not knowing how it should else happen, that it had rained blood into them. A very memorable instance of this took place at the Hague in the year 1670. Swammerdam, who relates it, tells us that one morning the whole town was in an uproar on finding, as they thought, their lakes and ditches full of blood; for these having certainly been full of water the night before, they agreed that it must have rained blood during the night. But a certain physician went down to one of the canals, and taking home a quantity of this blood-coloured water, he examined it by the microscope, and found that the water was water still, and had not at all changed its colour; but that it was full of prodigious swarms of small red animals, all alive, and very nimble in their motions, the colour and prodigious number of which gave a reddish tinge to the whole body of the water in which they lived. The certainty that this was the case, did not however persuade the Hollanders to part with the miracle. They prudently concluded, that the sudden appearance of such a number of animals was as great a prodigy as the raining of blood would have been; and remain assured to this day, that this portent foretold the scene of war and destruction that Louis XIV. afterwards brought into that country, which had previously enjoyed forty years of uninterrupted peace.

The animals which thus colour the water of lakes and ponds are the pulices arborescens of Swammerdam, or the water-flea with branched horns. These creatures are of a reddish-yellow or flame colour. They live about the sides of ditches, under weeds, and amongst the mud; and are therefore the less visible, except at a certain time, which is in the beginning or end of June. It is at this time that these little animals leave their recesses to float loose about the water, and meet for the propagation of their species; and by this means they become visible in the colour which they give the water. The colour in question is visible, more or less, in one part or other of almost all standing waters at this season; and it is always at the same season that the bloody waters have alarmed the ignorant.

The raining of frogs is a thing not less wonderful in the accounts of authors who love the marvellous than those of blood or stones; and this is supposed to happen so frequently, that there are multitudes who pretend to have been eye- witnesses of it. These rains of frogs always happen after very dry seasons, and are much more frequent in the hotter than in the cold countries. In Italy they are very frequent; and it is not uncommon to see the streets of Rome swarming with young frogs and toads in an instant after a shower of rain. Nay, they have been seen to fall through the air down upon the pavements. This seems to be a strong circumstance in favour of their being rained down from the clouds; but, when strictly examined, it comes to nothing. For these frogs which are seen to fall are always found dead, lamed, or bruised by the fall, and never hop about like the rest; and they are never seen to fall, except close under the walls of houses, from the roofs and gutters of which they have accidentally slipped down. Some people who love to add to things strange others yet stranger, affirm that young frogs have fallen into their hats in the midst of an open field; but this is equally ill and false.

Others, who cannot agree with the opinion of their falling from the clouds, have tried to solve the difficulty of their sudden appearance, by supposing them hatched out of the egg, or spawn, by these rains. Nay, some have supposed them to be made immediately out of the dust. But there are unanswerable arguments against all these suppositions. Equivocal generation, or the spontaneous production of animals out of dust, is now wholly exploded. The fall from the clouds would destroy and kill these tender and soft-bodied animals. And they cannot be at this time hatched immediately out of eggs, because the young frog does not make its appearance from the egg in form, but has its hinder legs enveloped in a skin, and is what we call a tadpole; and the young frogs are at least a hundred times larger at the time of their appearance than the egg from which they should be hatched.

It is beyond a doubt that the frogs which make their appearance at this time were hatched and in being long before. But the dry seasons had injured them, and kept them sluggishly in holes or coverts; and all the rain does is enlivening them, giving them new spirits, and calling them forth to seek new habitations, and enjoy the element they were destined in a great measure to live in. Theophrastus, the greatest of all the naturalists of antiquity, has affirmed the same thing. We find that the error of supposing these creatures to fall from the clouds was as old as the time of that author; and also that the truth in regard to their appearance was as early known; though, in the ages that followed, authors have taken care to conceal the truth, and to hand down to us the error. We find this venerable sage, in a fragment of his on the generation of animals which appear on a sudden, ridiculing the opinion, and asserting that they were hatched and living long before. The world, however, owes to the accurate Signor Redi the great proof of this truth, which Theophrastus has only affirmed. This gentleman, dissecting some of these frogs, found in their stomachs herbs and other half-digested food; and, openly showing this to his credulous countrymen, asked them whether they thought that nature, which engendered, according to their opinion, these animals in the clouds, had also been so provident as to provide grass there for their food and nourishment?

To the raining of frogs we ought to add the raining of grasshoppers and locusts, which have sometimes appeared in prodigious numbers, and devoured the fruits of the earth. There has not been the least pretence for supposing that these animals descended from the clouds, though they appeared on a sudden in prodigious numbers. The naturalist, who knows the many accidents attending the eggs of these and other like animals, cannot but know that some seasons will prove particularly favourable to the hatching them; and the prodigious number of eggs that many insects lay could not but every year bring us such abundance of the young, were they not liable to many accidents, and had not provident nature taken care, as in many plants, to continue the species by a very numerous stock of seeds, of which perhaps not one in five hundred need take root in order to continue an equal number of plants. It is thus also in regard to insects; and hence it cannot but happen, that if a favourable season encourage the hatching of all those eggs, a very small number of which alone is necessary to continue the species, we must in such seasons have a proportional abundance of them. More than half a century ago, there appeared in London such a prodigious swarm of the little beetle called the lady-cow, that the very posts in the streets were everywhere covered with them. But, thanks to the progress of philosophy amongst us, we had nobody to assert that it rained cow-ladies, but we contented ourselves with saying that it had been a favourable season for their eggs. The prodigious number of a sort of grub, which, about the same period, did vast mischief to the corn and grass, by eating off the roots, might also have been supposed to proceed from its having rained grubs, by people fond of making everything a prodigy; but our knowledge in natural history assured us, that these were only the hexaped worms of the common hedge-beetle called the cockchafer.

The raining of fishes has also been a prodigy much talked of in France, where the streets of a town at some distance from Paris, after a terrible hurricane in the night, which tore up trees, blew down houses, and did other damage, were found in a manner covered with fishes of various sizes. Nobody here made any doubt of these having fallen from the clouds; nor did the absurdity of fish, of five or six inches in length, being generated in the air, at all startle the people, or shake their belief in the miracle, until they found, upon inquiry, that a very well-stocked fish-pond, which stood on an eminence in the neighbourhood, had been blown dry by the hurricane, and only the great fish left at the bottom of it, the smaller fry having been tossed into their streets.

Upon the whole, all the supposed marvellous rains have been owing to substances naturally produced on the earth either never having been in the air at all, or only carried thither by accident.