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from which he computed, at the distance of Lisbon... about a degree of a great circle from Lisbon, Oporto. and a degree and a half from Oporto. In consequence of this supposition, he added 3 minutes to the interval between the time when the shock was felt at Lisbon, and at the several other places. The first column in the table. contains the names of places; the 2d, the distances from the assumed point, reckoned in half degrees; the 3d, the time that the earthquake took up in travelling to each, expressed in minutes; and the 4th contains the time in which the wave was propagated from its source to the respective places, expressed in minutes likewise.
In computing the times in this table, allowance was made for the difference of longitude, as it is laid down in the common maps, which are not always greatly to be depended on. The times themselves also are often so carelessly observed as well as vaguely related, that many of them are subject to considerable errors; the concurrent testimonies however are so many that there can be no doubt about the main point; and that the errors might be as small as possible, Mr. M. not only endeavoured to select those accounts that had the greatest appearance of accuracy, but, in all cases where it was to be had, always took a mean among them. In many of the accounts the relaters say only between such hours, or about such an hour.
It is observable, in the preceding table, that the times which the wave took up in travelling are not in the same proportion with the distances of the respective places from the supposed source of the motion; this however is no objection against the point assumed, since it is manifest, wherever it was, that it could not be far from Lisbon, as well because the wave arrived there so very soon after the earthquake as because it was so great, rising, as we are told, at the distance of 3 miles from Lisbon to the height of 50 or 60 feet. The true reason of this disproportion seems to be the difference in the depth of the water; for, in every instance in the above table, the time will be found to be proportionably shorter or longer as the water through which the wave passed was deeper or shallower.
Sect. 8.-If we would inquire into the depth at which the cause lies that occasions any particular earthquake, Mr. M. knows of no method of determining it, which does not require observations not yet to be had; but if such could be procured, and they were made with sufficient accuracy, he thinks some kind of guess might be formed concerning it: for, 1st, in those instances where the
vapour discharges itself at the mouths of volcanos, (as in the case of the earthquake at Lima,) it might perhaps be possible for a careful observer to trace the thickness of the several strata from thence to the place where the earthquake took its rise, or at least as far as the shore, if it took its rise from under the sea. If this could be once done in any one instance, and the velocity of such an earthquake nicely determined, we might then guess at the depth of the cause in other earthquakes, where we knew their velocity, by taking the depths proportional to those velocities, which probably would answer very nearly. 2ndly, If, in any instance, it should be possible to know how much the motion of any earthquake was retarded by passing under the ocean, the depth of the ocean being known, the depth at which the vapour passed would be also; for the velocity under the water would be to the velocity if there had been no water in the subduplicate ratio of the weight in the latter case to the weight in the former; allowing earth to be about 24 times the weight of water, the depth will be readily found. 3dly, Let us conceive the earth to be formed according to the idea before given of it, and that the same strata are at a medium of the same thickness for a very great extent, as well in those places where several of the upper ones are wanting as where they are not. On this supposition we may discover the depth at which the vapour passes, by comparing the several velocities of the same earthquake in places where the thicknesses of the superincumbent mass are different.
As the observations relating to the earthquake of Nov. 1st, 1755, are too gross, it would be in vain to attempt, by any of the foregoing methods, to determine with any certainty the depth at which the cause of it lay; but if Mr. M. might be allowed to form a random guess about it, he would suppose, (on a comparison of all circumstances,) that it could not be much less than a mile, or a mile and half, and he thinks it is probable it did not exceed 3 miles.
LVI. Observations on the Comet of Feb. 1760. By the Abbé De la Caille,* F. R. S. Dated Paris, Feb. 18, 1760. P. 635.
I will venture to send you some of my observations on the present comet, because bad weather may have prevented it from being seen in England.
* M. De la Caille, a celebrated French astronomer, was born at Rumigny, in 1713, and died at Paris in 1762, at only 49 years of age. He was educated at the College of Lisieux at Paris. Here he became the friend of Cassini de Thury, with whom he was associated in projecting the meridian line to pass through France. In 1739 he was appointed professor of mathematics in the Mazarine college; and in 1741 elected a member of the Academy of Sciences. In 1750 he went to the Cape of Good Hope to observe the stars in the southern hemisphere. His writings are very numerous, excellent, and greatly esteemed, especially his Elements of Astronomy.
These observations, with another made at Marseilles, on the first day, at 9h 55m 38 equal time, when the longitude of the comet was found in N 23° 29′ 46′′, and its north latitude 31′ 20′′, enabled him to compute the elements of its orbit. Its motion is direct. The ascending node is in § 19° 42′ 0′′, and the place of the perihelion in 8 26° 41′ 22′′. The inclination of the orbit is 80° 51′ 30', and the distance of the perihelion of the radius of the orbit of the earth. The comet passed the perihelion Nov. 25, 1759, at 20h 55m, mean time at Paris.
LVII. Extracts of some Letters from Signor Abbate de Venuti, F. R. S. to J. Nixon, A. M., F. R. S. relating to several Antiquities in Italy. p. 636. Sig. V. had bought a relievo, which in his opinion was very singular. It was of marble, 2 palms wide, and 1 high, and represented in a neat taste, a faun, with a tail and wings; which latter circumstance had never occurred to his observation before. He seemed to be dancing, and his dog at his feet in the same attitude. Near him was a tree, to which was tied a very elegant open chariot (thensa,) and beneath it there appeared a table, such as were used in entertainments, with a goblet on it, charged with relievo in embossed work.
He also met with a cornelian, on which was engraved a man cloathed with a pallium, and sitting on a chair: before him there appeared a lighted furnace, and on it a vessel of glass, or earthen ware. The artist himself held in his hand a pair of iron pincers, with handles, to take off the vessel from the fire, without burning himself.
Remarks on the preceding Extracts. By John Nixon, A. M., F.R.S. p. 639.
These throw no light on the above antiquities.
LVIII. A Catalogue of the Fifty Plants from Chelsea Garden, presented to the Royal Society by the Company of Apothecaries, for the Year 1759. By John Wilmer, M.D. P. 644.
This is the 38th presentation of this kind, completing to the number of 1900 different plants.
LIX. Of the Animal* sent from the East Indies, by General Clive, to His Royal Highness the Duke of Cumberland, which is now in the Tower of London. By James Parsons, M.D., F.R.S. P. 648.
This animal is something taller than the largest sized cat, being about 15 inches high at the shoulders; slender and light, though strong. The head is small in proportion to the rest, and the neck slender. It has nothing fierce in its aspect, but is mild, and very tame. It is exactly of a fawn-colour, having its ears black on their outsides, and lined with white hairs, and some white round the root of each ear; it is also white under the throat and belly, and a little so on the backs of its limbs. Its eyes are small, and its head like that of a cat, but somewhat slenderer; its legs are genteel and straight, with the paws of a cat, having the power of dilating and contracting its toes, which are armed with strong crooked nails, in the same manner as a cat or tyger does; and its actions are like those of a cat. Dr. P. sat and watched its motions, and saw it lick its foot, and rub it over its face several times exactly like a cat; and was told by the man who showed it, that when offended, it hisses. Dr. P. examined its teeth, and found them in the same number and manner with those of a cat. As to its food, they give it raw mutton every day; and when sick, which it often is, they give it a live fowl, or rabbit, which it seizes eagerly, and lies upon it without motion, for a considerable time, to suck the blood, and this proves a certain cure. The tail is like that of a cat also.
None of the natural historians have yet any account of this animal, except the learned Dr. Walter Charleton, who has a bad figure of it, where the head. is, contrary to truth, very large and strong in appearance, the tail like that of a fox, and the whole as strong as a mastiff dog: the name given it in the plate is the same with this, but differently spelled, thus, Siyah-ghush.
LX. Of the Frog-fish of Surinam. By Mr. George Edwards, F.R.S.
In the appendix to Merian's Nat. History of the Insects of Surinam, where she treats of the transformation of fishes into frogs, and of frogs into fishes, after explaining how the European frog is changed from a minute fish, or tad
• This animal is the Felis Caracal of the Gmelinian edition of the Systema Naturæ of Linneus, and belongs to that division in the genus which contains such species as have the ears terminated by pencil of hairs. It is a native of the eastern regions, and particularly, (as it is said) of Persia. Its general size is that of a fox, and its colour a light reddish bay. The figure given by Dr. Parsons is by no means remarkable for its elegance. In the Count de Buffon's History of Quadrupeds is a much superior representation. The caracal is an animal of great strength and fierceness, and is said to be occasionally tamed by the Persians, and used for the chace of various game.
pole, into a perfect frog, she proceeds to describe the gradual transformation of a species of frogs found in great numbers in the river-of Surinam, into perfect fishes, and gives 5 figures to illustrate her description; the subjects she says were then in the collection of Albert Seba at Amsterdam, from whom she also had her figures and information, as appears since by the account published by Mr. Seba of his curious cabinet of natural history, in two folio volumes, a copy of which, finely illuminated, is now in the British Museum.*
LXI. Of a Remarkable Operation on a Broken Arm. By Mr. Charles White, Surgeon at Manchester. Dated Manchester, March 27th, 1760. p. 675. This communication contains an account of a fracture of the humerus in a boy 9 years old, which not being united at the expiration of 6 months from the accident, Mr. White recommended (instead of amputation which had been proposed) to make a longitudinal incision down to the bone, to bring out one of the ends of it, (which might be done with great ease as the arm was very flexible) and to cut off the oblique end either by the saw or cutting pincers; then to bring out the other end of the bone, and to cut off that likewise; afterwards to replace them end to end, and then treat it entirely as a compound fracture. This proposal was at length acceded to, and the operation was performed. After the dressings were finished, the limb was placed in a fracture box contrived on purpose; the lad was confined to his bed, and the rest of the treatment was the same as that of a compound fracture.
The wound was nearly healed in a fortnight's time, when an erysipelas came on, and spread itself all over the arm, attended with some degree of swelling: this by fomentations and the antiphlogistic method soon went off, and the cure proceeded happily without any interruption. In about 6 weeks after the operation, the callus began to form, and was grown quite firm at the above date; that arm was as long as the other, but somewhat smaller by such long continued bandage; he daily acquired strength in it, and it was thought he would soon be fit to be discharged from the hospital.
* The history of the Rana paradoxa of Linneus, and of its tadpole, commonly called the Frogfish of Surinam, is now much better understood than in the days of Madam Merian and Seba, when the absurdities mentioned in the account here extracted by Edwards, seem to have been generally believed. The larva or tadpole in this species of frog is of larger size than usual, and even exceeds that of the full-formed animal when first arrived at its perfect state. This, however, is not entirely peculiar to the present species, but takes place in some others. In the British Museuni is a specimen both of the Rana paradoxa and of its tadpole, which appear to have been wanting in that collection at the time the present paper was written.