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was first eroded, and the hair-like fibres remained floating in the vefsel. Nor does the degree of transparency of the retina invalidate the evidence of its fibrous structure, fince Leeuwenhoek has thewn that the crystalline humour itself consists of fibres. (Arcania Nar turæ, V. 1. p.70.)
• Hence it appears, that as the muscles have larger fibres intermixed with smaller quantity of nervous medulla, the organ of vifion has a greater quantity of nervous medulla intermixed with smaller fibres; and it is probable that the locomotive muscles, as well as the vascular ones, of microscopic animals have much greater tenuity than these of the retina. · And besides the similar laws, which will be shewn in this
paper to govern alike the actions of the retina and of the muscles, there are many other analogies which exist between them. They are bota originally excited into action by irritations, both act nearly in the same quantity of time, are alike strengthened 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 those of the murçular 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 spasmodic actions of the retina; his fifth section is almost entirely occupied with that subject. Thougha we must therefore question the juftness of a theory which reits on so uncertain a foundation, we think Dr. Darwin's experiments, in general, are properly diversified, and he has illustrated them with great perspicuity.
Art. XVII. Observations on some Causes of the Excess of the Mortality of Males above that of Females. By Joseph Clarke, M. D. It is found, froin 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 seems to be compensated. In different countries, however, the proportions are observed to be unequal; whence arifes fome doubt respecting the final causc usually afligned for the fuperior number of males born in mott of the European climates. But some other facts of consequence fee in to be eftablished by the accurate paper now before is. Dr. Clarke observes that males grow to a greater lize than females; and that they require a better formation of the pelvis to pass with equal safety. "In great towns, therefore, where the conftitutions of the inothers are affected by luxury and local causes, the life of the male fætus is more uncertain than that of the female; not only by the greater difficulty attending their birth, but because they require niore plentiful nutrition. From this latter circum
ftance, Dr. Clarke informs us that near į more twins die, and near į are still-born, than of single children.
In the second letter Dr. Clarke examines more particularly the fize and weight of new-born infants of each sex. On an average, the weight of a new-born male was found to be seven pounds, five ounces, seven drachms, the circumference of the head fourteen inches, and the dimentiuns from ear to ear seven inches and a quarter ; while, in females, the former was fix pounds, eleven ounces, fix drachms; and the latter 138-7 The following observations are worthy of being presented to our readers :
• In reckoning children, weighing from 5 to 61,6 pounds weight, and from 6 to 71, 7, and so forth, in order to avoid fractions, I find the numbers of males and females, arranged according to their weight, to ttand as follow:
• Hence it appears that the majority of males runs thus : seven, eight, fix, five; whilst that of the females is seven, fix, five, eight, Hence also appears the merciful dispensations of Providence towards the female sex; for when deviations from the medium standard occur, it is remarkable that they are much more frequently below than above this standard. In izo instances there are only five children exceeding eight pounds and an half in' weight. The fame may be observed with regard to the fize of their heads. Only fix measured above 14 inches in circumference, and these all of the male sex; five measured 141, and one 15. In transverse dimensions only four ex. ceeded 7, the largest of which was 8}; whereas deviations under the standard in these particulars were very numerous, never, however, under 12 around and 64 across.'
Art. XVIII. Some particulars of the present State of Mount Vesuvius; with the Account of a Journey into the province of Abruzzo, and a Voyage to the Illand of Ponza. By Sir William Hamilton, K. B. F. R. S, and A.S. Among the various objets of curiosity in this interesting paper, Sis William Hamilton describes the Lake of Celaro, and the emissary to drain it constructed by the Einperor Claudius; the latter of which is a most magnificent monument of antiquity. The outlet is now filled up with rubbish; and, what is remarkable, the lake increales, while, in every other part of the world, the water, except from a change in its course, seems to lessen in quantity.
In the description of the island of Stephano, we meet with curious account of the provident foresight of hawks, which seizę
the quails, as they arrive from Africa, and lay them up
in separate parcels, according to the time at which they are killed, and eat them in the order of their staleness, while the greedier gulls devour them at once.
Art. XIX. An Account of a new Electrical Fish. By Lieutenant William Paterson. This fish 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. Paterson is of opinion that it belongs to the genus Tetrodon. It gave a strong electrical fhock even when it was weak.
Art: XX. Observations of the Transit of Mercury over the Sun's Disc, made at Louvain, May 3, 1786. By Nathanie! Pigott, Esq. F.R.S.
Art. XXI. Obfervation of the late Transit of Mercury over the Sun, observed by Edward Pigott, Esq at Louvain. The emerfion of the centre of Mercury, from the sun'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 Observations on making a Thermometer for measuring the higher Degrees of Heat. By Mr. Josiah Wedgwood, F.R.S. In our Review for February last we mentioned Mr. Wedgwood's first attempt on this subject. The thermometer he constructed was made of the calx of iron and clay; a composition which was observed to allume, from different degrees of fire, such a number of distinct colours and hades, as promised to afford critoria of the respective 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 easy to explain. They consisted, however, partly in the different pressure which different parts of the thermometer received in its formation, and somewhat on its form. Difficulties likewise arose from a diversity in the clay; which, though taken from the same stratum, and the fame depth, exhibited a difference in the degree of contraction, sometimes in the lower heats, at others in the higher degrees. To mention these difficulties is the most that we can do on the present subject; 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 Astronomical Observations ; together with a Recommendation of the Method of determining the Longitude of Places by Observations of the Moon's Transit over the Meridian. By Edward Pigott, Elą. According to Mr,
Pigott's observations, the latitude of York is 53° 57' 45"; its longitude is 4' 31" west of Greenwich.
Art. XXIV. Advertisement of the expected Return of the Comet of 1532 and 1661, in the Year 1788. By the Rev. Nevił Mask-lyne, D.D. F.R.S. Dr. Halley at first supposed the comets of 1532 and 1661, from the similarity of the elements of their orbits, to be one and the fame; and though he afterwards seemed to retract this opinion, it has been generally adopted by aftronomers. They accordingly expected its return, making an allowance for its fupposed retardation in 1789. Agreeably to this conjecture, Dr. Maskelyne 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 instance, however, the expectation of astronomers has been disappointed; and it reinains for future obfervations to ascertain the period.cal 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 suggested hy Sir Isaac Newton, who perceived its utility; and, since that time, many eminent mathematicians have made it a subject of inquiry. The method proposed by Mr. Vince is not only fimple and convenient, but appears to be entirely new.
Art. XXVI. Conjectures relative to the Petrifactions found in St. Peter's Mountain, near Maestricht. By P. Camper, M.D. F.R.S. Among those petrifaćtions, discovered in 1770, were fome large jaw-bones, which M. Hoitinan supposed to have belonged to a crocodile ; but in this he doubtlets was mistaken. They were found with corals, madrepores, alcyoniums, echinites, belemnites, turtle, and other bones, evidently pertaining to sea animals, and not to an amphibious reptile, usually found in ri
They likewife differed from the crocodile's jaws in leveral respects, particularly in having teeth on the palate. The vertebræ are evidently not those of a crocodile, which have transverfe futures; and the parts divided are clearly not epiphyles. Neither are the articulations of the fossil vertebrä siinilar to those of a crocodile. On the whole; it seems probable that these fofiil jaw-bones belonged to the respiring filhes, and perhaps to the genus delphinus.
Art. XXVII. Catalogue of One Thousand new Nebute and Clusters of Stars. By William Herschel, LL.D. F.R.S. Thefe nebula have been discovered entirely by Dr. Herschel, and give a Itrong confirmation to his opinion that we are fitu-ated within a system of Itars. The catalogue is preceded by very ingenious contrivances to take an extentive survey of the
different parts of the hemisphere 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 situation of the apparatus.
Art. XXVIII. Investigation of the Cause of that indistinctness of Vision which has been ascribed to the Smallness of the Optic Pencils. By William Herschel, LL.D.F.R.S. Different writers on optics have maintained that vision will be indiftinct when the optic pencils are less than the 40th or goth part of an inch. Dr. Herschel, however, has found that he could see clearly the bristles 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 indistinctness arose not from the cause generally imagined, but from the want of a just proportion between the aperture of the focal length of an object-glass or speculum. The 34th part of the focal length is not a sufficient aperture for the object-lens.
The usual list of presents 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 subjects of this work.
ART. VIII. The Memoirs of Khojeh Abdulkurreem, a Cashmerian
of Distinction, who accompanied Nadir Shah on his Return from Hindotan to Persia ; from whence he travelled to Baghdad, Damascus, and Aleppo, and, after visiting Medina and Mecca, embarked on a Ship at the Port of Jeddel, and failed to Hooghly in Bengal. Including the History of Hindoftan from A.D. 1739 to 1749; with an Account of the European Settlements in Bengal, and on the Coast of Coromandel. Translated from the original
Persian by Francis Gladivin, Eją. 8vo. gs. sewed Mackay, ; Calcutta. 1788.
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 modest account of himself and his work. He tells us he was born in the land of Cathmeer, the semblance of the celestial paradise, the inheritance of our great ancestor ; that, like him, he was banished from his native foil, but with this difference, that Adam's exile was the consequence of fin. When Nadir Shah invaded Hindoftan he dwelt in the city of Shahjchanabad (or Dehly). He had long wished to make a pilgrimage to Mecca, to visit the holy shrine, and. to kiss the feet of the