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SHOWER OF PUMICE-STONES.
5. Surprising Shoal of Pumice-stones found floating on the Sea.
By John Dove *.
On the 22d of March, 1724-5, at noon, being in the latitude of 35° 36′ south, and longitude 4° 9' west, with variation 3° 16′ W. they discovered several pumice-stones on the sea; but not expecting any such thing at that distance from the land, the islands Tristan d'Acunha being the nearest, which were judged to bear W. 9° 10 S. distance 186 leagues, they disputed what it might be ; when about one P. M. they took up a piece in a bucket, which confirmed Mr. Dove's opinion of its being pumice stones. Towards night it was spread all round, as far as could be seen. Next morning the pumice-stones were very thick, in drifts, lying N.N.E. and S.S.W. and extended out of sight from the mast head, increasing as they ran to the eastward.
Wednesday the 24th they continued their course E.S.E. 140 miles, the pumice-stones being thicker; so that for sixteen hours some of the drifts were about a cable's length broad, and so thick, they could scarcely see the water between them; and there was much the same breadth between the drifts, with several pumicestones interspersed. Towards noon, they found the pumice some. what thinner latitude 37° 35′ S. and longitude 1°4′ W.
Thursday the 25th, in the evening, the drifts were near as large as above, but towards next morinng they decreased much; so that about noon they were clear of the pumice-stones, several of which were as large as a man's head. They sailed 317 miles since they first discovered them. They lay just in the track for ships out. ward bound; and all the ships that went out the same year and since, who go so far to the southward, have fallen in with them, In the morning they tried the current, but found none and no ground at 130 fathoms. At noon, latitude 37° 54′ S. longitude 0° 38′ E. they judged Tristan d'Acunha bore W. 3° 39' N. Distance 256 leagues, supposing it to lie in latitude 37° 5′ S. and lon. gitude 15° 38′ W.
[Phil. Trans. 1728.
• We give this curious article a place here, as the pumice-stones must neces sarily have fallen down in showers.-EDITOR.
Shower of Fishes.
By Robert Conny.
On Wednesday before Easter, anno 1666, a pasture field at Cranstead, near Wrotham, in Kent, about two acres, which is far from any part of the sea, or branch of it, and a place where are no fish-ponds, but a scarcity of water, was all overspread with little fishes, conceived to be rained down, there having been at that time a great tempest of thunder and rain; the fishes were about the length of a man's little finger, and judged by all who saw them to be young whitings. Many of them were taken up, and showed to several persons. The field belonging to one Ware, a yeoman, who was at that Easter Sessions one of the grand inquest, and carried some of them to the sessions at Maidstone in Kent, and he showed them, among others, to Mr. Lake, a bencher of the Middle Temple, who had one of them, and brought one to London. The truth of it was averred by many that saw the fishes lie scattered all over that field. There were none in the other fields adjoining: the quantity of them was estimated to be about a bushel.
[Phil. Trans. 1698.
It is probable that these fishes were absorbed from the surface of the water by the electric suction of a water-spout; or brushed off by the violence of a hurricane. The phænomenon, though surprising, has occurred in various countries; and occasionally in situations far more remote from the coast than that before us *.
On the Nature of Snow.
1. Configuration of its Crystals.
By Dr. Grew.
Ir Aristotle aud Descartes, &c. who bave written of meteors, and amongst them of snow, have not given a full account of it, it will
* For the fall of aërolites, or meteoric stones, see chapter xlvi. section vii.
not be needless to inquire further of it. He that will do this, will do it best, not by the pursuit of his fancy in a chair, but with his eyes abroad; where if we use them well fixed, and with caution, and this in a thin, calm, and still snow, we may by degrees observe: 1st. with M. Descartes, and Mr. Hook, that many parts of snow are of a regular figure; for the most part, as it were so many little rowels or stars of six points; being perfect and transparent ice, as any we see on a pool or vessel of water. On each of these six points are set other collateral points, and those always at the same angles as are the main points themselves. Next, among these irregular figures, though many of them are large and fair; yet from these taking our first item, many others, alike irregular, but much smaller, may likewise be discovered. Again, among these not only regular, but entire parts of snow, looking still more warily, we shall perceive that there are divers others, indeed irregular, yet chiefly the broken points, parcels and fragments of the regular ones. Lastly, that besides the broken parts, there are some others which seem to have lost their regularity, not so much in being broken, as by various winds, first gently thawed, and then frozen into little irregular clumps again.
From hence the true notion and external nature of snow seems to appear, viz. that not only some few parts of snow, but originally the whole body of it, or of a snowy cloud, is an infinite mass of icicles regularly figured; that is, a cloud of vapours being gathered into drops, the said drops forthwith descend; on which descent, meeting with a soft freezing wind, or at least passing through a colder region of air, each drop is immediately frozen into an icicle, shooting itself forth into several points on each hand outward from its centre: but still continuing their descent, and meeting with some sprinkling and intermixed gales of warmer air, or in their continual motion and waftage to and fro, touching upon each other, some are a little thawed, blunted, frosted, clumpered, others broken, but the most clung in several parcels together, which we call flakes of snow.
It being known what snow is, we perceive why, though it seems to be soft, yet it is truly hard; because true ice; seeming only to be soft; because on the first touch of the finger on any of its sharp edges or points, they instantly thaw; otherwise they would pierce our fingers like so many lancets. Why again, though snow be
true ice, and so a hard and dense body, yet very light; because of the extreme thinness of each icicle in comparison of its breadth. Also how it is white, not because hard; for there are many soft bodies white; but because consisting of parts all of them singly transparent, but being mixed together appear white; as the parts of froth, glass, ice, and other transparent bodies, whether soft or hard.
Thus much for the external nature of snow; let us next a little inquire into its essential nature. Now if we would make a judg. ment of this, I think we may best do it by considering what the general figure of snow is, and comparing the same with such regular figures as we see in divers other bodies. As for the figure of snow, it is generally one, viz. that which is above described: rarely of different ones, which may be reduced chiefly to two generals, cir. culars and hexagonals, either simple or compounded together. More rarely, either to be seen of more than six points; but if so, then not of eight or ten, but twelve. Or in single shoots, as so many short slender cylinders, like those of nitre. Or by one of these shoots, as the axle tree, and touching upon the center of a pair of pointed icicles, joined together as the two wheels. Or the same hexagonal figure, and of the same usual breadth; but conti. nued in thickness or profundity, like the stone which Boetius calls Astroites. All these I say are rare, the first described being the general figure *.
[Phil. Trans. 1673.
To determine the quantity of water a given quantity of snow is equal to, we have an ingenious article in the same journal from the pen of Mr. Alexander Brice of Kirknewton, dated May 13, 1766; in which he observes, that from the end of March 1765 to the end of September of the same year, they had very little rain in that part of Scotland, and less snow in proportion: the rivers were as
* In an article in a subsequent volume by M. J. C. Beckman, we have the following notice of another variety in the form of snow. On the 1st of March last, there fell an unusual kind of snow, which I considered with more than ordinary attention. It had none of the ordinary figures, but was made up of little pillars, whereof some were tetragonal, some hexagonal, with a neat basis. On the top they were somewhat larger, as the heads of columns are. Consi dering the whole shape, we thought fit to give it the name of Nix Columnaris.
low, through the winter, as they used to be in the middle of sum. mer; springs failed in most places, and brewers and maltsters were obliged, even in winter, to carry their water from a considerable distance.
In the end of March last, they had a fall of snow; and, as he did not remember to have ever read an account of such an experiment, he wished to be able to determine, to what quantity of rain this fall of snow was equal. The snow had been falling from five o'clock the former evening, till ten o'clock next day; about eleven o'clock he measured the depth of the snow, and found it to be 6.2 inches; he then took a stone jug, holding about three English pints, and turned the mouth of it downwards on the snow mea. sured, and where the ground below was smooth, and hard; and by this means he took up all the snow from top to bottom in the jug; this snow he melted by the side of a fire, and the 6.2 inches of snow yielded six-tenths of an inch deep of water in the same jug. After emptying the jug, he dried, and weighed it in a balance, and took up the same quantity of snow in it as before, weighed it again, and found the weight of the snow taken up, and from this weight com puted what quantity of water it should have produced, and found that it should have produced 6-10ths of an inch, and 1-20th of an inch more; he then dissolved the snow, and found that it yielded a quantity of water in the bottom of the jug, 6-10ths of an inch deep as in the former experiment. The difference of 1-20th of an inch in the depth of the water, between the weight and the melting of the snow, was probably owing to an exhalation from the jug, while the snow was melting by the fire, for he observed a steam sometimes rising from it. A greater or less degree of cold, or of wind,
while the snow falls, and its lying a longer or shorter time on the ground, will occasion a difference in the weight, and in the quan. tity of water produced, from a certain number of cubic feet, or inches, of snow; but if he may trust to the above trials, which he endeavoured to perform with care, snow, newly fallen, with a moderate gale of wind, freezing cold, which was the case of the snow he made the trials on, the 27th of March last, will produce a quan. tity of water equal to 1-10th part of its bulk; or the earth, when covered with snow, ten inches deep, will be moistened by it when melted, or rivers and springs recruited, as much as if a quantity of