was firft eroded, and the hair-like fibres remained floating in the veffel. Nor does the degree of tranfparency of the retina invalidate the evidence of its fibrous ftructure, fince Leeuwenhoek has thewn that the crystalline humour itself confists of fibres. (Arcana Na? turæ, V. 1. p. 70.)

Hence it appears, that as the muscles have larger fibres intermixed with a smaller quantity of nervous medulla, the organ of vifion has a greater quantity of nervous medulla intermixed with fmaller fibres; and it is probable that the locomotive mufcles, as well as the vafcular ones, of microfcopic animals have much greater tenuity

than thefe of the retina.

And befides the fimilar laws, which will be fhewn in this paper to govern alike the actions of the retina and of the mufcles, there are many other analogies which exift between them. They are both originally excited into action by irritations, both act nearly in the fame quantity of time, are alike ftrengthened or fatigued by exertion, are alike painful if excited into action when they are in an inflamed ftate, are alike liable to paralyfis, and to the torpor of old age.'

According to the arguments above advanced by the author, he confounds the functions of the nerves with thofe of the mufçular fibres; for we have no evidence of contraction taking place in fibres purely medullary. But this is not the only part where he speaks of the fpafmodic actions of the retina; his fifth fection is almost entirely occupied with that fubject. Though we must therefore queftion the juftnefs of a theory which refts on fo uncertain a foundation, we think Dr. Darwin's experiments, in general, are properly diverfified, and he has illustrated them with great perfpicuity.

Art. XVII. Obfervations on fome Caufes of the Excefs of the Mortality of Males above that of Females. By Jofeph Clarke, M. Ď. It is found, from the examination of registers, that the number of males born exceeds that of females; but, by the greater proportion of males who die at an early age, this difference feems to be compenfated. In different countries, however, the proportions are obferved to be unequal; whence arifes fome doubt refpecting the final caufe ufually afligned for the fuperior number of males born in moft of the European climates. But fome other facts of confequence feem to be eftablifhed by the accurate paper now before us. Dr. Clarke obferves that males grow to a greater fize than females; and that they require a better formation of the pelvis to pafs with equal fafety. In great towns, therefore, where the conftitutions of the mothers are affected by luxury and local causes, the life of the male foetus is more uncertain than that of the female; not only by the greater difficulty attending their birth, but because they require more plentiful nutrition. From this latter circum

itance,

ftance, Dr. Clarke informs us that near more twins die, and near are ftill-born, than of fingle children.

In the fecond letter Dr. Clarke examines more particularly the fize and weight of new-born infants of each fex. On an average, the weight of a new-born male was found to be seven pounds, five ounces, feven drachms, the circumference of the head fourteen inches, and the dimenfions from ear to ear seven inches and a quarter; while, in females, the former was fix pounds, eleven ounces, fix drachms; and the latter 13-73. The following obfervations are worthy of being presented to our readers:

In reckoning children, weighing from 5 to 61,6 pounds weight, and from 6 to 7, 7, and fo forth, in order to avoid fractions, I find the numbers of males and females, arranged according to their weight, to ftand as follow:

Males.

Females.

lbs. 4 5 6. 7 8 9 10 lbs. 4 5 6 7 8 9 10 No. O 3 6 32 16 2 N°. 2 9 14 25 8

2

Hence it appears that the majority of males runs thus: feven, eight, fix, five; whilst that of the females is feven, fix, five, eight. Hence also appears the merciful difpenfations of Providence towards the female fex; for when deviations from the medium ftandard occur, it is remarkable that they are much more frequently below than above this ftandard. In 120 inftances there are only five children exceeding eight pounds and an half in weight. The fame may be obferved with regard to the fize of their heads. Only fix measured above 14 inches in circumference, and thefe all of the male fex; five measured 14, and one 15. In tranfverfe dimenfions only four exceeded 7, the largest of which was 8; whereas deviations under the ftandard in thefe particulars were very numerous, never, however, under 12 around and 64 across.'

Art. XVIII. Some particulars of the prefent State of Mount Vefuvius; with the Account of a Journey into the province of Abruzzo, and a Voyage to the Ifland of Ponza. ́ By Sir William Hamilton, K. B. F. R. S. and A. S. Among the various objects of curiofity in this interefting paper, Sir William Hamilton defcribes the Lake of Celaro, and the emiffary to drain it conftructed by the Emperor Claudius; the latter of which is a moft magnificent monument of antiquity. The outlet is now filled up with rubbish; and, what is remarkable, the lake increafes, while, in every other part of the world, the water, except from a change in its courfe, feems to leffen in quantity.

In the defcription of the island of Stephano, we meet with curious account of the provident forefight of hawks, which feize

the

the quails, as they arrive from Africa, and lay them up in feparate parcels, according to the time at which they are killed, and eat them in the order of their ftalenefs, while the greedier gulls devour them at once.

Art. XIX. An Account of a new Electrical Fish. By Lieutenant William Paterfon. This fifh was found at Joanna, one of the Comora islands. It is a coral island; and the fish was caught in one of its hollows. Mr. Paterfon is of opinion that it belongs to the genus Tetrodon. It gave a strong electrical fhock even when it was weak.

Art. XX. Obfervations of the Tranfit of Mercury over the Sun's Difc, made at Louvain, May 3, 1786. By Nathaniel Pigott, Efq. F. R. S.

Art. XXI. Obfervation of the late Tranfit of Mercury over the Sun, obferved by Edward Pigott, Efq at Louvain. The emerfion of the centre of Mercury, from the fun's limb, differed 53' from the time allotted by M. de la Lande, allowing for the difference of the meridians between Paris and Louvain.

Art. XXII. Additional Obfervations on making a Thermometer for measuring the higher Degrees of Heat. By Mr. Jofiah Wedgwood, F. R.S. In our Review for February last we mentioned Mr. Wedgwood's first attempt on this fubject. The thermometer he constructed was made of the calx of iron and clay; a compofition which was obferved to affume, from different degrees of fire, fuch a number of diftinct colours and fhades, as promised to afford critoria of the refpective degrees. This ingenious artist in making his thermometer, for the account of which we must refer to the number abovementioned of our Journal, had to encounter with difficulties which it is not eafy to explain. They confifted, however, partly in the different preffure which different parts of the thermometer received in its formation, and fomewhat on its form. Difficulties likewife arose from a diversity in the clay; which, though taken from the fame ftratum, and the fame depth, exhibited a difference in the degree of contraction, fometimes in the lower heats, at others in the higher degrees. To mention thefe difficulties is the most that we can do on the prefent fubject; for the prosecution of which, as it cannot be rendered intelligible by any abridgment, we must refer our readers to the work.

Art. XXIII. The Latitude and Longitude of York determined from a Variety of Aftronomical Obfervations; together with a Recommendation of the Method of determining the Longitude of Places by Obfervations of the Moon's Tranfit over the Meridian. By Edward Pigott, Efq. According to Mr.

Pigott's

Pigott's obfervations, the latitude of York is 53° 57′ 45′′; its longitude is 4' 31" weft of Greenwich.

Art. XXIV. Advertisement of the expected Return of the Comet of 1532 and 1661, in the Year 1788. By the Rev. Nevil Mafkelyne, D.D. F.R.S. Dr. Halley at firft fupposed the comets of 1532 and 1661, from the fimilarity of the elements of their orbits, to be one and the fame; and though he afterwards feemed to retract this opinion, it has been generally adopted by aftronomers. They accordingly expected its return, making an allowance for its fuppofed retardation in 1789. Agreeably to this conjecture, Dr. Mafkelyne had calculated that it might be expected at its perihelium about the beginning of the year 1789, certainly before the 27th of April. In this inftance, however, the expectation of aftronomers has been disappointed; and it remains for future obfervations to afcertain the periodical return of this eccent ic planet.

Art. XXV. A new Method of finding Fluents by Continuation. By the Rev. S. Vince, A. M. F. R. S. This problem was fuggefted hy Sir Ifaac Newton, who perceived its utility; and, fince that time, many eminent mathematicians have made it a fubject of inquiry. The method proposed by Mr. Vince is not only fimple and convenient, but appears to be entirely new.

1

Art. XXVI. Conjectures relative to the Petrifactions found in St. Peter's Mountain, near Maeftricht. By P. Camper, M.D. F. R. S. Among thofe petrifaćtions, difcovered in 1770, were fome large jaw-bones, which M. Hofman fuppofed to have belonged to a crocodile; but in this he doubtlefs was miftaken. They were found with corals, madrepores, alcyoniums, echinites, belemnites, turtle, and other bones, evidently pertaining to fea animals, and not to an amphibious reptile, ufually found in rivers. They likewife differed from the crocodile's jaws in feveral refpects, particularly in having teeth on the palate. The vertebræ are evidently not those of a crocodile, which have tranfverfe futures; and the parts divided are clearly not epiphyfes. Neither are the articulations of the foffil vertebræ fimilar to thofe of a crocodile. On the whole, it feems probable that thefe foffil jaw-bones belonged to the refpiring fithes, and perhaps to the genus delphinus.

Art. XXVII. Catalogue of One Thoufand new Nebuke and Clufters of Stars. By William Herfchel, LL. D. F. R. S. Thefe nebulæ have been difcovered entirely by Dr. Herfchel, and give a strong confirmation to his opinion that we are fituated within a fyftem of ftars. The catalogue is preceded by very ingenious contrivances to take an extenfive furvey of the

different

ན་

different parts of the hemifphere in one night. The author can, by means of these and his telescope, which is likewise described, follow any object in the firmament for near a quarter of an hour, without disturbing the fituation of the apparatus.

Art. XXVIII. Investigation of the Caufe of that indiftinctnefs of Vision which has been afcribed to the Smallness of the Optic Pencils. By William Herfchel, LL. D. F. R. S. Different writers on optics have maintained that vifion will be indiftinct when the optic pencils are less than the 40th or 50th part of an inch. Dr. Herfchel, however, has found that he could fee clearly the briftles on the edge of the wing of a fly, when the optic pencil was only the 173d part of an inch. By pursuing his researches, he at last discovered that the indiftinctnefs arose not from the caufe generally imagined, but from the want of a juft proportion between the aperture of the focal length of an object-glafs or fpeculum. The 34th part of the focal length is not a fufficient aperture for the object-lens.

The ufual lift of prefents and donors concludes the present volume, which, in point of curious research and utility, has afforded us more gratification than we commonly reap from detailing the fubjects of this work.

ART. VIII. The Memoirs of Khojeh Abdulkurreem, a Cashmerian of Distinction, who accompanied Nadir Shah on his Return from Hindoftan to Perfia; from whence he travelled to Baghdad, Damafcus, and Aleppo, and, after visiting Medina and Mecca, embarked on a Ship at the Port of Feddee, and failed to Hooghly in Bengal. Including the History of Hindostan from A. D. 1739 to 1749; with an Account of the European Settlements in Bengal, and on the Coast of Coromandel. Tranflated from the original Perfian by Francis Gladwin, Efq. 8vo. 5s. fewed Mackay, Calcutta. 1788.

THE

HESE Memoirs are interefting, rather from the fituation than the talents of their author. He introduces them by a preface, in which, though in the luxuriance of the oriental style, he gives a modeft account of himself and his work. He tells us he was born in the land of Cafhmeer, the femblance of the celeftial paradife, the inheritance of our great ancestor; that, like him, he was banifhed from his native foil, but with this difference, that Adam's exile was the confequence of fin. When Nadir Shah invaded Hindoftan he dwelt in the city of Shahjchanabad (or Dehly). He had long wifhed to make a pilgrimage to Mecca, to vifit the holy fhrine, and to kifs the feet of the

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