It is suspected that great degrees of electrifying have occasioned some women to miscarry; and no wonder that such sudden shocks should do it.

Mr. King, the experimenter, observes, that a piece of linen that has never been washed, will soon give a good degree of electricity to a large warm glass tube; viz. on account of the mealy paste, which weavers dress the linen with; and therefore any piece of linen thus dressed will do,

The Dr. gave an account, in the General Evening Post of Sept. 1747, of the great benefit of ventilators in Newgate, and in the Success frigate for Georgia, which lay five months wind-bound in our channel with the transports for Cape Breton, the rest of which were all very sickly; but in the Georgia frigate, in which were about 300 men, all were in good health, and they got all in health to Georgia.

On the Cure of a Wound in the Cornea, and a Laceration of the Uvea in the Eye of a Woman. By Tho. Aery, M.D. N° 488, p. 411.

A poor widow, aged 26, of a pale complexion, was for several years at times subject to the colic. Dec. 26, 1744, she received a wound in the cornea of her right eye, by the spear of a common fork, which also divided the uvea. Part of the aqueous humour was discharged, the eye lost its transparency, had a violent pain in it, and she could only distinguish objects when she looked down. Dr. A. ordered her a collyrium prepared of the bals. tolut. camphor. solut. in sp. vin. aq. plantag. cum pauxillo tinct. mart. Mynsicht. A few drops of this blood-warm was to be used frequently; to bleed her, largely in the arm, and her diet was to consist of water-gruel, aq. hord. and fresh broth.

Next day she had no pain in the eye, but complained she saw motes floating before it: he ordered her a purge, and an astringent fomentation to her temples and eyelids. The day following the eye was inflamed, and the lids tumefied, and she had a pain in her head. The collyrium was changed for rose-water and vinegar, aa 3 ss. roche alum gr. v. 3 drops twice a day. The 29th the inflammation increasing, the purge and bleeding were repeated, and the parts were fomented only with spirit of wine. The 31st the inflammation continued to decrease, till after a fright. Jan. 5th the inflammation increasing, the sides of the wound became a little protuberant. The purge was repeated, and a blister laid behind the right ear, and an emollient collyrium was used: next day the swelling of the eyelids was gone: the 11th she had a show of the menses, and the wound appeared healed: from the 15th to the 24th the inflammation continued to abate; only one day it increased by fretting and weeping much; but by bleeding she grew better, and so she continued to the 30th; except one day,. on catching cold, her eye became exceedingly inflamed, which was relieved by bleeding. Feb. 4, she had a little pain in her eye, and the tunica adnata looked

a little red. Soon after dropping in 2 drops of cold water, the eyelids swelled, and a violent inflammation of the eye ensued, with a speck appearing; but these symptoms went off by repeated applications of leeches and a mercurial purge. The 19th a sternutatory of hellebore and euphorbium was ordered. In a few days after the inflammation left her eye; when she complained she saw double; which complaint also soon left her.

The eye was myopical, and she saw the right side of objects a little darkened; yet she could read pretty small characters. The uvea was not united where it was divided, but still retained its natural power of contraction; the transparency of the humours and convexity of the cornea were the same as before; there was no scar on the cornea; the shape of the pupil was much altered.

On catching cold she was subject to a slight pain in her eye. At the above date there remained no other alteration than what he had just mentioned, and what necessarily followed from the contraction of the pupil, the not admitting a sufficient quantity of rays to pass to the retina, on which account she was short-sighted. Her seeing objects darkened on one side, might proceed from the artificial part of the pupil being situate nearer to the great canthus of the eye than usual in nature; by which the rays which fall on the side of the cornea, next to the little canthus of the eye, being partly intercepted, must occasion a defect in the picture; from which defect a darkness will be seen on one side of the object. To the weakness of the vessels of the eye we may attribute the pain of the eye on catching cold: it often happens to those who have had a severe ophthalmia, that during life the small vessels are too weak; and hence, from slight causes being distended, they will be painful and frequently red.

When her eye had little or no appearance of inflammation, he tried cold water, but with rather bad success. All cold applications to inflamed eyes, astringents or repellents, require the utmost caution in applying them; for if they produce not a good, they will produce a bad effect. In slight cases they often have very happy effects, but where the obstruent matter is so fixed that it will not suffer itself to be easily repelled back, the vessels being straitened, the fluids coagulated, the disease will be increased; which happened in this case from the application of cold water.

The good effects of evacuations are very evident in abating the inflammation. Wounds in the cornea, attended with a wound of the uvea, and a troublesome ophthalmy, heal without any scar.

Tables of Specific Gravities, extracted from various Authors, with some Observations on the same. By Richard Davies, M. D. N° 488, p. 416. The ancients have left but few particulars concerning the different specific gravities of bodies, though it is plain they were in the general sufficiently acquainted

with them. It was by the knowledge of the various weights of gold and silver, that Archimedes is recorded to have detected the noted fraud committed in Hiero's crown, as Vitruvius has at large related in his Architecture, 1. ix, c. 13; and it is from the same great philosopher that we have derived the demonstration of those hydrostatical rules, by which the proportions are best to be known, of the several weights or densities of different bodies, having the same bulk or magnitude: as may be seen in his tract De Insidentibus Humido, lost in the Greek original, but retrieved in great measure, as it is said, from an Arabic translation. It was published in Latin, with a commentary by Frederic Commandine, at Bononia 1565, 4to, and the substance of it by Dr. Barrow in his Archimedes, printed likewise in 4to, at London 1675.

Pliny, in the 18th book of his Natural History, has set down the proportional weights of some sorts of grain, among which he says that barley is the lightest. And the same author, in his 33d book, speaking of quicksilver, observes that it is the heaviest of all substances, gold only excepted. Which Vitruvius had also taken notice of, and had mentioned besides the weight of a known measure of it, that of 4 Roman sextarii.

Again, Q. Rhemnius Fannius Palæmon, in his fragment De Ponderibus et Mensuris, has given an observation, of the proportional gravities of water, oil, and honey; stating that the sextarius of either water or wine weighed 20 oz. the same measure of oil 18, and of honey 30. Their specific weights were therefore in proportion as 1.0, 0.9, and 1.5, exactly agreeable to what Villalpandus determined about the beginning of the last century; yet was this author himself sensible that these were not to be considered as very nice experiments. After which he proceeds to describe a pretty good instrument for readily finding the different specific gravities of fluids; and shows how those of solids also may be hydrostatically discovered.

Francis Bacon, Lord Verulam, &c. in his Historia Densi et Rari, has given a table, which he calls, Tabula Coitionis et Expansionis Materiæ per Spatia in Tangibilibus (quæ scilicet dotantur pondere) cum Supputatione Rationum in Corporibus Diversis. This tract does not appear to have been published till after his death, which happened in the year 1626, but was probably written several years before; and the experiments were, as he tells us, even made long before that. Hanc tabulam multis abhinc annis confeci, atque ut memini, bona usus diligentia. It is probably therefore the oldest table of specific gravities now extant. The experiments there mentioned were not made hydrostatically, but with a cube of an ounce weight of pure gold, as he says, to which he caused cubes of other materials to be made equal in size: as he did also two hollow ones of silver, and of equal weights, the one to be weighed empty, and the other filled with such liquid. as he wanted to examine. He was himself sensible that his experiments of this 3 Z

VOL. IX.

sort were, notwithstanding his care, very defective. From among these, notwithstanding their imperfection, as they appear to have been some of the first experiments of the sort regularly digested, and as they were besides made by so great a man, Dr. D. has extracted the specific gravities of the fixed metals, which he has inserted as examples in the following tables, after reducing them to the common form, on the supposition that pure gold was, according to Ghetaldus, just 19 times as heavy as water. And this he rather chose to do, than to make use of his Lordship's own weight of water given in the table, which in the manner he took it could not be very exact, and which besides would not have brought out the specific gravity of pure gold more than 18 times as much; and that of the other metals in proportion. This table contains in all 78 articles.

There are also in the 3d volume of the folio edition of his works, p. 223, Certain experiments made by the Lord Bacon about weight in air and water. These are truly hydrostatical, but very imperfect, Dr. D. has not therefore inserted any of them in the following collection.

Marinus Ghetaldus, a nobleman of Ragusa, published in 4to, at Rome, in 1603, his treatise entitled, Promotus Archimedes, seu de Variis Corporum Generibus Gravitate et Magnitudine Comparatis, where he has given a comparison between the specific gravities of water and eleven other different substances, from his own hydrostatical experiments, made with care and exactness. These are here inserted; expressing the numbers as they stand in his own book, but Dr. D. has afterwards also for uniformity reduced them to the decimal form. He has besides, at the end, transcribed at large the 2 tables of this author, in which every one of the 12 sorts of bodies, he treats about, is successively compared with all the others, both in weight and magnitude.

same.

Father Johannes Baptista Villalpandus, a Jesuit of Cordova in Spain, in his Apparatus Urbis et Templi Hierosolymitani, printed in folio at Rome, in 1604, exhibited a table of the proportional weights of the 7 metals and some other substances, from his own experiments, made with great care, as he tells us, by the means of 6 equal solid cubes of the fixed metals, and a hollow cubical vessel 8 times as large, for the comparing mercury, honey, water, and oil with the His numbers, which are inserted under his name in the following tables, were also again published by Joh. Henr. Alsted, in his Encyclopædia Universa, printed in 2 vol. in folio, at Herborn, 1630, and by Henry Van Etten, in his Mathematical Recreations, whence they have been often transcribed into other books. Villalpandus's book, which is only the 3d volume of a work begun to be published several years before, was itself printed so soon after Ghetaldus's, that it is probable he either never saw that author, or not at least till after his own experiments were made.

Mr. Edmund Gunter, in his Description and Use of the Sector, printed after

his death by Mr. Samuel Foster in 1626, having occasion to mention the specific weights of the several fixed metals, quoted Ghetaldus, and made use of his proportions, and so did also Mr. William Oughtred, in his Circles of Proportion, first published in 4to, 1633, with this only difference, as to the form, that he changed Ghetaldus's unit into 210, by which he expressed all his relations in whole numbers. It is likewise probable that D. Henrion took from the same place the numbers he applied in his Usage du Compas de Proportion, printed at Paris in 1631, 8vo; though he has not given them all with exactness, for the sake as it seems of using simpler vulgar fractions.

Father Mersenne, a French minim, in his Cogitata Physico Mathematica, printed at Paris in 1644, 4to, has given from the observations of his accurate friend Petre Petit, a table of the specific gravities of the metals and some other bodies, making gold 100, water 5, and the rest in proportion. These are here reduced to the common form, and inserted under his name in the following tables. The same were afterwards made use of by Father Francis Milliet de Chales, Jesuit, in his Cursus Mathematicus, Mons. Ozanam, Professor Wolfius, and several others. Dr. D. has not seen Petit's own book, but it was entititled L'Usage ou le Moyen de Pratiquer par une Regle toutes les Operations du Compas de Proportion-augmentées des Tables de la Pesanteur et Grandeur des Metaux, &c. had a privilege dated in 1625, though it is said not to have been printed till some years after. The same Father Mersenne has also taken notice, in his general preface, of a table of 20 specific gravities, some time before published by Mons. Aleaume, which he there sets down; but which he also observes are very incorrect. Dr. D. has not therefore inserted any of them in this collection. Mr. Smethwick, one of the earliest members of the Royal Society, communicated to the same in July 1670, the weights of a cubic inch of several different substances, said to have been formerly taken by Mr. Reynolds in the Tower of London. This gentleman was the same who composed several tables relating to the price of gold and silver, which were published in a book entitled the Secrets of the Goldsmith's Art, at London, 1676, in 8vo. These weights are expressed in decimals of an avoirdupois pound, are carried to 8 places of figures, and seem to have been carefully and accurately collected. Dr. D. has therefore in the following tables reduced them to the common form, in order to give them their proper authority with the rest. He knows not whether these weights were ever before printed or not, neither can he give any account, after what particular manner the experiments were made, from which they were taken. They were communicated to him from the register books of the Royal Society; and he only observes, that the absolute weight here assigned of a cubic inch of common water, does not differ more than a small fraction of a grain, from the weight of the same afterwards determined by Mr. Ward of Chester.