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MONTHLY REVIEW,

For N O V EMBER, 1772.

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ART. I. Transactions of the American Philofophical Society, held at Phia

ladelphia, for promoting useful Knowledge. Vol. I. From Jan. !, 1769, to Jan. 1, 1771. 410. 12 . Philadelphia printed by Bradford; and fold by Dilly in London. 10 trace the progress of science through the various na

tions and ages of the world, to mark the several periods of its rise, glory, and decline, to investigate the causes of its prosperity or decay, and to observe the complexion of the times, with the political state of those countries in which science has been either cultivated or neglected, are objects highly worth the attention of the historian and philosopher, and would furnish a great variety of very important, amusing, and useful information.

To execute such a task would indeed require a greater com. pass of knowledge and discernment than falls to the share of any single person, and would be attended with a degree of application and labour, which few would be willing to encounter. The records of the remoter nations and ages are few and imperfect; and the more modern discoveries and improvements in science are so numerqus and various, that the necessary materials for such a history could not be collected without an expence which no private fortune could defray, and without such a fund of knowledge, and such vigour of application, as no single person, however curious, intelligent, and resolute, can, be thought to possess. Would princes unite in affording patronage to such an undertaking, and employ a sufficient number of the ablest men in every department of science for this truly valuable purpose, it would be productive of consequences much more desirable and beneficial than any which can arise from the more expensive pursuits of ambition, and the rage of conquests. VOL. XLVII,

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A defign of this kind, whatever difficulties might attend it, is not altogether in practicable; and the Writer of this article is not without hopes, as well as withes, that a period will arrive, in which such a fcheme, however imaginary it now appears, may be accomplished. The establishment of literary societies in different parts of the world must greatly contribute to facilitate such an undertaking. Their transactions, carefully preserved and published, serve as a repository of useful materials for those who, in any future time, may have inclination and encouragement to attempt a talk, so laudable and so important. These may be considered as so many treafuries, into which every one throws his mite, in order to augment the general stock: and they are free of access to all who wish to en sich themselves by the contributions of others.

In this view only such establishments are very important and useful : and the several members and patrons of them may be respected as the directors and guardians of science, ever disposed to encourage and affilt the studious and inquisitive.

But this is not the only advantage accruing from fuch literary establishments. Every friend of science has an interest in this common stock, and is desirous of repaying into it, with improvement, the contributions he has received. There is a degree of reputation and honour in being connected with the friends of science, to which no liberal and ingenuous mind can be insensible. It serves to excite a laudable ambition ; and, we may add, that united views and labours promise a much fpeedier and higher advancement in useful knowledge, than the separate efforts of individuals. If we appeal to fact, we shall find that the progress of science, of mathematical and philosophical science especially, has been surprisingly accelerated since the establishment of literary associations in the various nations of Europe: and it is certain, however other causes may have conspired, that such associations have not a little contributed to this end. What may we not expect from the spreading of similar institutions, formed on the most liberal and laudable principles, in other parts of the globe ? In this view the American Philosophical Society, instituted for promoting useful knowJedge in general, and those branches thereof in particular as may be more immediately serviceable to the British colonies,' claims peculiar notice.

As to the origin of this Society, we are informed, in the in. troduction to the volume before us, that, two Societies having formerly subasted in Philadelphia, whose views and ends were the same ; viz. the advancement of useful knowledge, it was judged that their union would be of public advantage; and they were accordingly united January 2, 1769, by a certain fundamental agreement; the chief articles of which are ift. That the name of the united fociety shall be The American Philosophical Society, held at Philadelobia, for promoting useful Knowledge. 2dly. That there Thall be the following officers of the Society; viz. one Patron, one President, three Vice-Presidents, one Treafurer, four Secretaries, and three Curators. . 3dly. That all the above officers shall be chosen annually by ballot, at the first meeting of the Society in January, excepting only that inftead of electing a Patron, the Governor of the province be requested to be Patron."

We have likewise a brief account of the laws and regulations of the Society. It appears from the list for the years 1770 and 1971, that Dr. Franklin, a gentleman universally known and esteemed in the literary world, was elected their first Prea fident, and that the number of members is near 300. Useful knowledge is the leading object of this inftitution; and therefore the members propose to confine their difquifisiens, principally to such subjects as tend to the improvement of their country, and advancement of its interest and prosperity.' Å The publishers of this volume have prefixed to it a Mort acą count of the ancient and present state of that part of America now possessed by the English, and of the province of Philadelphia in particular. They have traced a very striking resemblance between this country and that part of China, which lies in the same latitude ; or that tract of land which forms the eastern fide of Asia, in respect of foil, climate, temperature of the air, winds, weather, and many natural productions: and they observe, that the same resemblance is remarkable between the western side of the old world and the western side of our continent; whereas the eastern and western sides of the same continent differ greatly.'

They thew in what respects the country is still capable of inprovement, and they lead the way to discoveries that may not only be beneficial to the Americans themselves, but may render them more useful to their mother country. They inform us, that though it will be a principal part of their business to inquire, and try to find out what their own country is capable of producing; what improvements may be made in agriculture, farming, gardening, &c. yet it is not proposed to confine the views of the Society, wholly, to these things, so as to exclude other useful subjects, either in physics, mechanics, astronomy, mathematics, &c. The chief merit (thus they conclude their preface) the Society mean to claim to themselves, is only that of encouraging and direciing inquiries and experiments; of receiv. ing, collecting, and digefting discoveries, inventions, and improvements ; of communicating them to the public, and distin. guishing the Authors; and of thus uniting the labours of many, to attain one end, namely, the advancement of useful know ledge and improvement of our country.'

In the prosecution of this very liberal and useful plan, we are persuaded they will have the best wishes and affiftance of all the friends of science and humanity. The specimen they have already given does honour to their ingenuiry and industry, and promites great advantage to every branch of ornamental and useful knowledge, from their future disquifitions and labours.

This volume is divided into four sections, each of which tontains a variety of articles on similar subjects. If these artis cles had been numbered, they might more easily have been referred to ; and this, though'a triling circumstance, is not altogether unworthy their attention, in their future publications,

In giving an account of this volume, we shall class its several articles under the heads of Astronomy, Mechanics, &c. as we have done in reviewing the Transactions of the Royal Society : and we shall begin with that which occupies the principal place in this collection, viz.

ASTRONOMY. The first article under this head is · A Description of a neza ORRERY, planned, and now nearly finished, by David RITTENHOUSE, A. M. of NORRITON, in the County of PHILADELPHIA,

This machine is to have three faces, perpendicular to the hosizon. From the center of that in the front, which is to be four feet square, arises an axis, to support a ball, representing the fun. Other balls, to represent the planets, are contrived to move in elliptical or bits, having the central ball in one focus, and to describe, as nearly as possible, equal areas in cqual times. The orbits of the planets are to be properly inclined to each other; their aphelia and nodes are to be justly placed ; and their velocities fo ordered, as to differ insensibly from the tables of astronomy in some thousands of years. This machine is furnished with three indexes, which point out the hour of the day, the day of the month, and year, answering to the situation of the heavenly bodies, then represented; they will serve this puse pose for a period of soco years, either forward or backward, There are other contrivances for determining the situation of a planet, as it may be observed, either from the earth or fun. One of the fmaller faces exhibits all the appearances of Jupi. tèr and Saturn, and of their fatellites : and the other represents all the phænomena of the moon, and the wbole process of solar and lunar eclipses in respect of time, quantity, and duration ; together with the sun's declination, equation of time, &c. The whole of this inachine may be adjuited by a pendulum clock, and the clock part of it may be contrived to play a great variety of iudic.

There. There is a great number of articles in this collection, relating to the transit of Venus in 1769. It would much exceed our limits to give a particular account of each of these. In some we have a description of the places of observation, and of the instruments made use of on this occafion; together with preli. minary experiments and observations, towards ascertaining the motion of their clocks, and the longitude of their several stations. In others, we have the observations themselves, with all the circumstances attending this rare and interesting phænomenon, minutely and accurately reported. Others exhibit a comparative view of the obfervations of astronomers in different parts of the world, together with the longitudes and latitudes of the places of observation; the method of calculating the parallax from these data, and the parallax itself. We thall only observe in general, that the astronomers in America have been no Jess skilful and diligent in improving and applying this curious phænomenon to useful purposes than their associates in other quarters of the globe. They have spared neither expence nor labour in procuring all necessary assistance and information ; they have been supplied and encouraged by the generosity of their friends; and, whilst others were disappointed by intervening clouds, the heavens were peculiarly propitious to their wishes and expectations.

In the appendix to the astronomical papers, we have two or three articles which deserve particular notice. The first is a letter from the Rev. Mr. Ewing to the Society, communicating an improvement in the contruction of Godfrey's (commonly called) Hadley's quadrant, not long since discovered. The greatest inconveniences arising from the former construction of this inftrument are owing to the badness of the glasses, the planes not being ground parallel to each other, and to its standing in need of a new and careful adjustment almost every time it is used. These imperfections, it is apprehended, are removed by the new construction : and this instrument will be peculiarly serviceable for finding the longitude at sea, by the observed dircance of the moon from the sun, or from a known star near her path, as angles may be measured by it with much greater precision than with the common quadrant. For these pure poses it is proposed, that the arch should contain 120 whole degrees, and be numbered from the middle to 120 both ways, and that instead of one central speculum, ewo should be fixed to the index, inclining to each other in an angle of 60 degrees. When thus adjusted, they are to be screwed fast by the inaker. The chief advantage attending this new construction is this, that the inftrument becomes hereby capable of affording a number of observations, so that by taking the mean of several, the

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