subsided with a copious white froth The Elbe rose in some places still more violently.

The Wonderful Configurations of the smallest shining Particles of Snow, with several Figures of them. By JOHN NETTIS, M.D.- [1755.]

THE weather being intensely cold in the year 1740, the snow which fell was hard, entire, and pellucid, and some particles being received on a pencil, were placed on a plane glass plate under the object-glass of the best microscopes: the greatest care was taken that the smallest particles might not be dissolved, either by the breath or perspiration of the hands, lest the little angles might by the least degree of warmth disappear. And thus, with this apparatus and these precautions, the extreme exactness and equality of the figures of their most minute particles might be observed and delineated.

Some consisted of long round spicule; others approached to a round figure made up of small globules; but these were observed to be opaque, as the air was disposed to thaw; but when the air was frosty, many slender hexangular figures appeared, some of equal, others of unequal sides.

Several little stars seemed to consist of six oblong, round, hexangular lamellæ, or indeed of six rays terminating in points; which little stars appeared to be formed of six plane rhomboidal particles. Several plane hexangular particles of equal sides, or oblong hexangulars, adhered to several of these stars, either at their extremities, or at each side of every ray. Some hexangular lamella of equal sides were adorned all round with six other lamellæ of the same figure and size, or with hexangular oblong lamellæ, and to these sometimes adhered several others, more or less. Many of these hexangulars were ornamented with six rays, and to these were fixed the most slender lamellæ, which were also hexangular, of equal or unequal sides: but of equal angles of 60 degrees; and to these lamellæ others like them adhered, some greater and some less, but most of the latter; and various others, like the fortifications of cities, appeared to be joined to long hexangular spiculæ, and plane hexangles of equal sides.

And though a vast variety of these configurations of snow may fail or vanish in the same moment, yet the smaller particles, from their various combinations with each other, con

stituting this wonderful variety of configurations of the snow, were observed by him to be comprehended under these following forms; viz. of parallelograms, or oblong, straight, or oblique quadrangles, rhombs, rhomboids, trapezia, or of hexangular forms of equal or unequal sides, whose angles are 60 degrees; and these hexangular particles were far more numerous than those of any other form.

The natural size of most of the shining quadrangular par

ticles, and of the little stars of snow, as well the simple as the less compound ones, does not exceed the twentieth part

of an inch; nor do the more compound particles the fifth of an inch.

Of the Fossil Shells called Orthoceratites. By EDWARD WRIGHT, M.D.-[1755.]

PELAGIAN or ocean shells are frequently found fossil very near the surface, as every naturalist knows; which proves, that such places have formerly been the sea-shore. The greatest depths of the sea, as yet sounded, have been found to be about 3000 fathoms, and the ordinary depths are about 150; which makes it evident, that such fossil shells ought never to be found at less depths in the earth than from 150 to 3000 fathoms..

Though fossil shells are to be found in almost all the lower parts of the surface of the earth, yet there are certain very large tracts, where such bodies are never found, viz. the mountains, which seem to be the remains of the original strata of the earth. In the Alps, Apennines, and Pyrenees, no shells nor marine bodies of any kind are to be found in the Ochels, a branch of the large Grampian mountains in Scotland, which Dr. W. had occasion diligently to examine, he could discover no marine bodies. The same is observed of all the large mountains of Africa, and of Asia; and in the huge chain of Cordilleras in Perou, Mons. e la Condamine searched in vain for such bodies. This kind of mountains, which indeed alone deserve that name, are chiefly composed of vitrifiable matter; and if they are sometimes found to contain sea-shells, it is never at great depths, nor in their original metallic or stony strata; though such bodies are found in great abundance at the foot of mountains, and in the adjacent vallies, in which there are many eminences in some parts continued in small chains, though but of little extent, which contain marble, sea-shells, chalk, and other calcinable matter, but never any veins of metal, though we frequently find in them pyrites, ochre, vitriols, and other minerals, which have been washed down from veins of iron and other metals, with which the higher mountains abound, and have afterwards been deposited in the calcareous strata of the valliés.

It is certain, that all our fossil shells are foreign to our climates, except such as are common to the whole globe. Besides, we find not only a very great quantity of fossil shells and other marine bodies, but also a great number of impressions of foreign plants, mostly of the capillary kind, on

slates and other stones; and it is now certain, that all the fossil wood of Loughneagh, in Ireland, (as in most other places where such wood is found) has been produced in a different climate. Bones, and even entire skeletons of rhinoceroses, elephants, and other foreign land animals, are discovered pretty commonly through all Europe. All these substances. are commonly found near to, or in the same strata with, fossil shells, and other marine bodies; and all of them, whether original productions of sea or land, appear evidently to have been deposited in the places where we now find them. There are many observations which seem to prove that the earth, or at least many parts of its surface, have suffered by fire; not to mention the marks of it observed on many mineral substances. The artificial production of potters earth or clay is a very strong argument in support of this opinion. Potters' earth, as is well known, is found plentifully in most low grounds and vallies, between mountainous tracts, and where calcareous strata abound. By exposing common flint-stones to the confined vapour of boiling water in Papin's digester, a clay of the very same kind may be formed, and is no more than a decomposition of the flints. Hence it would appear, that wherever this clay is to be found, there the earth has undergone some violence from fire.

Chalk is no more than the ruins of sea-shells, and limestone consists of the same bodies cemented together by a stony juice. Amber appears evidently to be the resin of trees (which are frequently found along with it at this day) united to the acid of sea-salt, which abounds in the earth. The reason of insects, straws, &c. being immersed in amber, absolutely inexplicable from the hypothesis of its being of mineral origin, is now no more a secret; for we know that nothing is more common, than to find such bodies immersed in the resin of trees. Fossil sea-salt, or salt-gem, seems to have been deposited in the quarries, whence it is dug. All or most part of pit-coal appears to be of diluvian origin, for it gives a caput mortuum, the texture of which exactly resembles that of burnt wood. Large forests have been buried, which have undergone a fermentation and putrefaction in the earth, so that the colour of the woody part has been changed, though the texture has remained entire enough to allow us to distinguish to what kingdom it belongs. All bitumens, asphaltum, petrolæum, &c. seem to be no more than productions of resinous substances united with mineral acids, which have caught fire in the earth by fermenting with heterogeneous matter, and have thus undergone a sort of

natural distillation and exaltation. These are more than chimerical notions, and are even demonstrated by experiments; for amber can be produced artificially, as also bitumens by the distillation of resinous substances with mineral acids; and there is great probability that pit-coal might be imitated.

An Account of what happened at Bergemoletto, by the tumbling down of vast Heaps of Snow from the Mountains there, on March 19. 1755.-[1756.]

IN the neighbourhood of Demonte, as in the upper valley of Stura, there were some houses in a place called Bergemoletto, which on the 19th of March, in the morning, were entirely overwhelmed and ruined by two vast bodies of snow that tumbled down from the upper mountain. All the inhabitants were then in their houses, except one Joseph Rochia, a man of about 50, who with his son, a lad of 15, were on the roof of his house, endeavouring to clear away the snow, which had fallen without any intermission for three preceding days. Whence perceiving a mass of snow tumbling down towards them from the mountain above, they had but just time to get down and flee, when, looking back, they perceived the houses were all buried under the snow. Thus 22 persons were buried under this vast mass, which was 60 English feet in height.

After five days, Joseph Rochia having recovered from his fright, and being able to work, got upon the snow, with his son, and two brothers of his wife's, to try if they could find the exact place under which his house and stable were buried; but though many openings were made in the snow, they could not find the desired place. On the 24th of April the snow was greatly diminished, and he conceived better hopes of finding out his house.

His wife's brothers, who lived at Demonte, went with Joseph and his neighbours to work upon the snow, where they made another opening, which led them to the house they searched for; but finding no dead bodies in its ruins, they sought for the stable, which was about 240 feet distant, and having found it, they heard a cry of "Help, my dear brother." Being greatly surprised as well as encouraged by these words, they laboured with all diligence till they had made a large opening, through which the brothers and husband immediately went down, where they found still alive, the wife about 45, the sister about 35, and a daughter