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MONTHLY REVIEW,

For DECEMBER, 1772.

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Art. I. PHILOSOPHICAL TRANSACTIONS. Vol. LXI. For the Year 1771. In Two Parts. 400.

18 s. fewed. Davis. 1772. STRONOMY generally fills a very considerable part of

the Philosophical Transactions of our Royal Society. In the present publication we have, under this division, first,

Art. 3

A Letter from Dr. FRANKLYN, F.R.S. to the Astronomer Royal;

containing an Observation of the Transit of MERCURY over the Sun, Nov. 9, 1769. By John Winthrop, Esq; F. R. S. Hollisian Professor of Mathematics and Natural Philosophy at Cambridge, New England.

Mr. IVinthrop had a favourable opportunity for observing the beginning of this phænomenon : the planet made an impression on the sun's limb at 2 h. 52'. 41".; and appeared wholly within at 53' 58". apparent time. This transit compleats three petiods of 46 years, since the first observation of Gassendi, at Patis, in 1631. Art. 13. Extract of two Letters from M. Messier, of the Royal

Academy of Sciences, and F.R. S. to M. de MAGALHAENS, on a new Comet. Translated by Dr. Bevis.

This comet was discovered on the roth of January 1771. Its nucleus appeared, in the telescope, of a whitilh complexion, and not very well defined; surrounded with an atmosphere several minutes wide, with a faint tail five or fix degrees long.

apparent motion was retrograde from the equator towards the North Pole, M. Meffier has been no less alliduous than accurate in his observation of the heavens. This, he tells us, is the twelfth comet he has discovered in thirteen years past.

M. Pingrè has deduced the elements of this comet's orbit from the observations of M. Metsier, and concludes from them, that it passed its perihelion the 22d of Nov. 1770; that it reVoL, XLVII.

sembles

Its

Tembles none of those whose elements are determined ; and tirat it may frequently have passed in the sun's neighbourhood imperceptible to the northern parts of the earth. Art. 14. Defcription and Use of a new construid Equatorial Ten

lescope, or portable Observatory, made by Mr. Edward Nairne, London.

We can give our Readers no tolerable idea of this inftrument, without the plate annexed to the article. The construction here described seems to be a valuable improvement.

Art. 43, 44, coistain several aftronomical and other observations made by Mr. Charles Green and Lieutenant James Cook, in their voyage, and during their stay at King George's (or as it is called by the natives, Otalseite) isand, in the South Sea.

Art. 45, gives an account of the late transit of Venus as it was observed by M. . Maurits Molt, in the New Observatory at Batavia. Art. 4.6. Kep'er's Method of computing the Moon's Paral'ax in So

lar Eclipjes, demon/irated and extended to all Degrees of the Moon's į atitude; as also to the cligning the Moon's correspondent apparent Diameter: Together with a concise Applicution of this Form of Calculation to tiofe Eclipses. By the late H. Pember

This paper contains a very ingenious and accurate solution of an abstruse problem in aftronomy.

As the moon's parallaxes continually vary during the progress of a solar eclipse, the repeated computation of thele renders the calculation of such eclipses very difficult and tedious. The compendium proposed by the famous Kepler, in his Rudolphine Tables, for this purpose, is by no means so clear and perfect as night be wished. To explain and demonstrate his method is the design of this article. Art. 49. Description of a Method of measuring Differences of right

Ascension and Declination, with Doilond's Micrometer; together with other new Applications of the same. By the Rev. Nevil Maskelyne, Astronomer Royal.

Mr. Dollond's divided object glass micrometer is, on various accounts, the most convenient and exact inftrument for measusing small diftances in the heavens, but is not so well adapred for measuring differences ct right afcenfion and declination as the common wire micrometer. The Author of this article proposes an easy and cheap contrivance in order to render ic fic for both these uses ; and he subjoins several neceffary instructions for using it with accuracy and advantage. Art. 51. An Account of the going of an Apronomical Clock. By

the Rev. Francis Woolaiton, F.R.S.

ton, M.D.

Art.

Art. 53. The Quantity of the Sun's Parallax as deduced from the

Observations of the Transit of Venus, on June 3, 1769. By Thomas Hornsby, M. A. Savilian Professor of Aftronomy in the University of Oxford, and F. R. S.

Mr. Hornsby makes the parallax on the 3d of June, by taking the mean result of several observations, 8". 65; whence the mean parallax will be found to be = 8.78; and if the semidiameter of the earth be supposed = 3985 English miles, the mean distance of the carth from the sun will be 93,726,900 English miles : and as the relative distances of the planets are known, their absolute distances, and consequently the dimena lions of the solar system, will be, as in the following table :

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Mercury, 387,10 36,281,700
Venus,

723,33 67,795,500
Earth, 1000,00 93,726,900
Mars, 1523,69 142,818,000
Jupiter,

5200,98 487,472,000
Saturn, 9540,07 894,162,000

MATHEMATICS. Art. 36. A Disquisition concerning certain Fluents, which are af

fignable by the Arcs of the Conic Sections ; wherein are inveslia gated some new and useful Theorems for computing such Fluents, By John Landen, F.R.S.

This disquisition is intended to supply a defect in theorems of a similar nature, proposed and exemplified by Mr. Maclaurin in his treatise of Fluxions, and Mr. D'Alembert, in the Memoirs of the Berlin Academy. As some of their theorems are partly expressed by the difference between the arc of an hypera bola and its tangent, and this difference is not directly attainable when such arc and its tangent are both infinite, a computation by such theorems must in all these cases be impracticable. To ascertain the limit of the difference abovementioned, and by means of this limit to facilitate the required computation, is Mr. Landen's object in this article. Art. 47. Of Logarithms. By the late William Jones, Efq;

F.R.S. It is a sufficient recommendation of this paper, that it is a genuine remain of that eminent mathematician the late Mr. Jones. No one better understood, and no one could better explain the nature and construction of logarithms. This article, though small, is an acceptable specimen of his unquestionable abilities in this department of science. As it will not admit of any extract or abridgment, we must refer our mathematical Readers co the paper itself.

[To be continued.)
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Art. II. ÉJays on the Spirit of Legislation, in the Encouragement of

Agriculture, Population, Manufactures, and Commerce. Containing Observations on the political Sy/tems at present pursued in various Countries of Europe, for the advancement of those effential Interefs. Tranflated from the original French, which gained the Premiums offered by the Society of Berne in Switzerland, for the best Compositions on this Subject. 8vo. 55. 3 d. Boards. Nicoll. 1772.

HE great objects in the domestic policy of nations are

commerce, agriculture, and the arts; and those citizens are usefully employed, who endeavour to investigate the proper methods of promoting their advancement. In the present publication we meet with several interesting memoirs on these important topics. The degrees of their merit are by no means equal; but in all of them we find a liberal and commendable fpirit of inquiry:

But while it is with real pleasure that, in the papers before us, we observe philosophy and jurisprudence applied to the lower as well as the higher precautions of civil government, we must acknowledge, that in perusing them we were sometimes led to imagine that men of letters were, in many respects, unequal to the minute investigation of the subjects attempted to be ex, plained in them. They cannot always obtain that information which practice communicates to the artisan, the labourer, and the man of business. A multitude of facts necessarily escape their attention; and, in their hafte to form conclufions, they too frequently forget that their premises are imperfect. Imagination and the spirit of hypothclis are consulted; and the inex. perienced Reader mistakes for the acquisitions of experience, the plausible pictures and inventions of an ingenious mind.

With this caution the present publication may be read, both with profit and satisfaction: even to those in power, to whom it chiefly addresles itself, it may exhibit views which they might profecute and improve with advantage. It is a melancholy reflection, however, that such men are not always solicitous to discharge, with honour, the important trusts with which they are invested. It happens frequently that they are unable, and they appear constantly unwilling, to attend to those minute details which alone can qualify them to act with propriety for the public grandeur and prosperity.

The following thoughts on the Freedom of Commerce,'may give our Readers an idea of the spirit of these memoirs :

• The eagerness for gain, so deeply imprinted in the minds of merchants, guaranties to us that they will always make every effort for extending commerce, without being in want of directions for each from government. It is not in states where they multiply ordonnances on commerce, and where they burthen it in a thousand ways, that it flourishes molt. These rules are commonly too varying and

changeable;

changeable; they either depend on passing circumstances, or they are gained by persons interested in obtaining great profits at the ex• pence of all other merchants. These fort of edicts are subject to contradict themselves from time to time; and as nothing is fixed, on which they could be founded, they only disconcert the enterprizes of the merchants. Fearing to find themselves traversed all of a sudden by unforeseen ordonnances, they dare not obey the calls of their genius, and cannot form succeslive projects. It is better to grant them an honeft liberty, which perinits them to hazard attempts for opening new branches of commerce.

• It is not that the bridle Mould be entirely relaxed in all points. If they know no other law than their avidity, they will often risque the prejudice, not only of the commerce, but also the agriculture and manufactures of a nation. It is, for example, mischievous to manufactures, and consequently to the commerce'of a state, to permit them to export and sell to ftrangers the raw materials upon which the arts are employed that are established in the country. England, so enlightened in its true intereits, knows well how to interdict her merchants exporting wool; and assuredly it is bad politics in Spain, to sell her wool to all other nations who will buy it, rather than work it up herself. It is also impoverishing a nation and discouraging her manufactures, to foffer them to import all sorts of foreign fabrics which might be made at home. These importations become above all burthensome, when, from neighbouring states, who can furnish immense quantities, and who at the same time, take care not to receive too much in exchange from other nations. In the same manner it is doing mischief to the agriculture of a country, to leave the merchants masters of importing at their will foreign corn, which sinks that at home to too low a price. For from thence it happens, that the cultivator not being sufficiently indemnified for his care and expences is disheartened, and works with languor, This is a case that is often found in the Pays-de-Vaud. When we have grain enough for our own consumption, we are exposed to receiving from Franche Comte great quantities, which prevent the hufbandman from selling his crops--engages him to neglect his lands, and renders him always more incapable of entering into a rivalry with his neighbours, upon the price of saleable commodities. All these examples prove sufficiently, that there are certain restrictions to which it is proper to subject merchants. But excepting cases of this nature we must leave them free.

• It is immediately visible, that we ought not to tax the sale of all that is fabricated in a country. When masters of exportation, preference should be given to the national manufactures. When all other nations are excluded from commerce, it is like the Japanese, who, to their great detriment, will not traffic with either the Chinese or Dutch. When they are restrained from selling merchandise, except to a single people, and under condition that a certain price is taken' for all, as is practised in a certain state. These sort of restrictions are ruinous to a nation. They prevent the sale of merchandise at a jaft price, and of profiting by the advantages. The merchants should rather be encouraged to carry their correspondence everywhere. The more markets they find, the more certain means they have of selling

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