Mr. Minors, an eminent surgeon and anatomist of the Middlesex Hospital; when he was in the army at Gibraltar, saw an entire skeleton, standing upright, in a dry rock, part of which had been blown up with gunpowder, in carrying on some works in the fortifications, which left the skeleton quite exposed. Indeed, the bones of elephants have been found in Sheppey Island, but much destroyed; their size and substance being so considerable, as to resist for a long time that decay which those of the human could not withstand. To these may be added the horns of large animals, as the elk, and others, which have been found in bogs, preserved as the bog-oak, &c. above mentioned.

The leaves of plants, whose fibres are firm and dry, will endure for a long time; but those of a succulent nature never can, as they putrefy very soon. We see the leaves of ferns of several kinds, polypodium, trichomanes, and other capillary plants, with nodules of stone formed about them; flags, reeds, rushes, equisetum, and many such, of a firm texture, are found in slate and stone; and even the iuli of trees are said to have been found fossil as their leaves.

Fig. 1.

All seeds, and the stones of fruits, having a firm texture, are also capable of being strongly impregnated with stony and pyritical matter; and doubtless the smaller seeds, if carefully looked for, might be found fossil, as well as these now produced, viz. such as have a firmness in the covering; but being small, and mixed with the dirt, sand, &c. probably is the reason of their being overlooked. Fruits of various kinds are found pe-co trified; but this is only in their green state,m when they are hard enough to endure till they are impregnated with stony or mineral particles.

Of impressions of fishes upon slate there are several kinds, which have such impressions on

Fig. 2.

them in some there remains only the bare impression, without any part of the fish; in others, the scales only, but retaining the entire form

of the animal; and in others, no parti

adheres to the slate but the skeleton, or part of it, most commonly the spine. He says that he always observed, that the bones are never seen but on the grey or blue slate, or their impressions. Fig. 1. a fig petrified when hard and green; fig. 2. coffeeberries; fig. 3. an exotic fruit, like a small melon.

On the Heat of the Weather in Georgia. By H. ELLIS, Esq.

It is now (writes Mr. Ellis) about three o'clock; the sun bears nearly S.W., and I am writing in a piazza, open at each end, on the N. E. side of my house, perfectly in the shade: a small breeze at S. E. blows freely through it; no buildings are nearer, to reflect the heat, than 60 yards: yet in a thermometer hanging by me, the mercury stands at 102°. Twice it has risen this summer to the same height; viz. on the 28th of June, and the 11th of July. Several times it has been at 100°, and for many days successively at 98°; and did not in the nights sink below 89°. It is highly probable that the inhabitants of this region breathe a hotter air than any other people on the face of the earth. The greatest heat we had last year was but 92°, and that but once: from 84° to 90° were the usual variations; but this is reckoned an extraordinary hot summer.

I have frequently walked 100 yards under an umbrella, with a thermometer suspended from it by a thread to the height of my nostrils, when the mercury has risen to 105°; which is prodigious. At the same time I have confined this instrument close to the hottest part of my body, and have been astonished to observe that it has subsided several degrees. Indeed I never could raise the mercury above 97° with the heat of my body. I have traversed a great part of the globe, not without giving some attention to the peculiarities of each climate; and I can fairly pronounce that I never felt such heats any where as in Georgia. I know experiments on this subject are extremely liable to error; but I presume I cannot now be mistaken, either in the goodness of the instrument, or in the fairness of the trials, which I have repeatedly made with it. This same thermometer I have had thrice in the equatorial parts of Africa; as often at Jamaica, and the West India islands; and on examination of my journals, I do not find that the quicksilver ever rose in those parts above the 87th degree, and to that but seldom: its general station was between the 79th and 86th degree; and yet I think I have felt those degrees, with a moist air, more disagreeable than what I now feel.

Yet these heats, violent as they are, would be tolerable but for the sudden changes that succeed them. On the 10th of December last, the mercury was at 86°; on the 11th it was so low as 38° of the same instrument.

Remarks on the several Accounts of the fiery Meteor, (which appeared on Sunday, the 26th of November, 1758,) and on other such Bodies. By JOHN PRINGLE, M.D. F.R. S.

THIS meteor seems to have been vertical at Cambridge, or nearly so, and to have appeared first there in a state of ignition. Thence it proceeded directly, almost N. W. by N., over several counties in England, over the Solway Frith, which it crossed between Carlisle and the town of Dumfries; and in Scotland over the shires of Dumfries and Lanerk; but soon after its becoming vertical to the last, viz. a few miles to the southward of Douglas, (or, perhaps, nearer to the borders of Lanerk and the shire of Ayr, about 10 or 12 miles to the eastward of Auchenleck,) part of the tail seemed to break off, and to disperse in bright sparks of fire; while the head, into which the remainder of the tail was instantly collected, moved on in the same direction, till coming over Fort William, in the shire of Inverness, after a course of about 400 miles, it there suddenly disappeared. But, notwithstanding the extinction of the meteor at this place, it seems still to have proceeded northwards; since it was seen again in a luminous state, in a globular form, but without a tail, about the 58° of latitude, on the western coast of the shire of Ross, almost vertical to the observer; moving then to the southward of the east, that is, in a direction almost contrary to the first; and in this last course, of which we know not the end, it possibly might have gone a great way to the eastward.

During the first part of its progress, viz. from Cambridge to Fort William, it went obliquely downwards in such a manner, that, by computation, it must have been from about 90 to 100 miles high at the first of these places, and between 26 and 32 miles at the last.

This dipping and rising in the course of a meteor is not more extraordinary than its lateral deviation from a straight line.

In regard to the velocity, it seems almost incredible; as we have sufficient data for computing it at the rate of 30 miles in a second. But if we allow that it only moved through half the space in that time, we shall find the progression of this body to have been above 100 times swifter than the mean celerity of a cannon ball, and nearly equal to that of the earth in its orbit round the sun.

As to its real size, we cannot pretend to determine that point with any precision, since its dazzling brightness would

S

occasion some deception, and the apparent magnitude haz been so differently represented by the observers.

The body must have been of a considerable bulk to have yielded such a light, as that, when in the zenith of Cambridge, a farmer at Ancram, at the distance of above 260 miles, should, on entering his threshold, see the whole side of his house illuminated by it; and, to use his own expression, with a brightness as of sunshine.

As for the tail, it was a stream of light several miles in length; for this was no deception, like what we suppose the train of a shooting star to be, but was either a real flame, or, what is more probable, it consisted partly of flame, but mostly of smaller masses of fire, (which the observers call sparks, when falling out of the lucid tract,) and of vapours or fuliginous particles not heated red-hot, but illuminated by the parts actually burning. Perhaps these vapours were the chief part of the composition, and which will account for its light being so much fainter than that of the head; since in some places where the air was less clear, or the distance greater, we find the whole meteor described either as a round ball, or a spheroid (with the largest axis in the direction of its motion), but without a tail. In this last case, viz. that of the oval form, it is probable that, besides the head, the beginning of the tail was also visible, as consisting of flame, and therefore brighter than the rest; and that both together appeared oblong to those observers. But such as were nearest, and had a clear atmosphere, saw the tail of a considerable length; that is, the flame, the sparks, and the illuminated vapour in a train behind the head, as being lighter, and therefore meeting with more resistance from the air; in the same manner as the flame, the sparks, and smoke of a torch are seen to follow it. All this is plain; but in regard to that separation of the third part of the tail from the rest, a circumstance clearly described by the farmer at Ancram, and seemingly confirmed by other observations, there may be some difficulty.

The final report, so frequently mentioned, not only heard by those who saw the light, but by others who knew nothing of what had happened, was a real sound, immensely greater than any we are acquainted with. For, at the distance of 70 miles and upwards, it was compared to loud thunder, the report of heavy artillery, the fall of the gable-end of the house the person was in, and to a musket fired off in the garret. If this noise was produced when the body threw out those masses of burning matter, by the observers called sparks of fire, the bursting of the tail, &c. we shall find that at this

1

time the meteor, by being more than 41 miles high, was in a region where the air is 3000 times rarer than on the surface of the earth; that is, about six times rarer than in a common exhausted receiver, where sonorous bodies are not heard, and even where gunpowder and the pulvis fulminans take fire, and are exploded, but without noise.

Dr. P. also concludes from the great report, that the substance of the meteor was of a firmer texture than what could arise from mere exhalations, whether formed into a sphere, and then burning, or disposed into a kind of train, and consumed by a running fire; for sounds, as far as we know, are either produced by the quick and violent percussions of hard bodies on the air, or by the sudden expansion of an elastic fluid, after being condensed within some solid substance. To these arguments for the solidity of this body, we may add its extreme velocity, and the intensity of the light; which are, likewise, circumstances more conformable to a heavy and solid substance than to one formed of exhalations only.

If it is, then, probable, that these balls of fire come from regions far beyond the reach of our vapours; if they approach often so near to the earth, and so seldom or never touch it; if they are moved with so much celerity, as in that respect to have the character of celestial bodies; if they are seen flying in all directions, and, consequently, have a motion of their own, independent of that of our globe, surely we are not to consider them as indifferent to us, much less as fortuitous masses, or trains of terrestrial exhalations in the ethereal regions.

The regular diurnal Variation of the horizontal magnetic Needle. By JOHN CANTON, M.A. F.R.S.-[1759.] THE number of days on which these observations were taken was 603; and the diurnal variation on 574 of them was regular; that is, the absolute variation of the needle westward was increasing from about eight or nine o'clock in the morning till about one or two in the afternoon, when the needle became stationary for some time; after that, the absolute variation westward was decreasing, and the needle came back again to its former situation, or near it in the night, or by the next morning. The diurnal variation is irregular when the needle moves slowly eastward in the latter part of the morning, or westward in the latter part of the afternoon; also when it moves much either way after night, or suddenly both ways within a short time. These irregularities seldom