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ART. I. PHILOSOPHICAL TRANSACTIONS. VOL. LXI.
STRONOMY generally fills a very confiderable part of the Philofophical Tranfactions of our Royal Society. In the prefent publication we have, under this divifion, firft, Art. 3.
A Letter from Dr. FRANKLYN, F. R.S. to the Aftronomer Royal; containing an Obfervation of the Tranfit of MERCURY over the SUN, Nov. 9, 1769. By John Winthrop, Efq; F. R. S. Hollifian Profeffor of Mathematics and Natural Philofophy at Cambridge, New England.
Mr. Winthrop had a favourable opportunity for obferving the beginning of this phænomenon: the planet made an impreffion on the fun's limb at 2 h. 52′. 41′′.; and appeared wholly within at 53. 58". apparent time. This tranfit compleats three periods of 46 years, fince the firft obfervation of Gaffendi, at Paris, 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. Tranflated by Dr. Bevis.
This comet was difcovered on the 10th of January 1771. Its nucleus appeared, in the telescope, of a whitifh complexion, and not very well defined; furrounded with an atmosphere feveral minutes wide, with a faint tail five or fix degrees long. Its apparent motion was retrograde from the equator towards the North Pole. M. Meffier has been no lefs affiduous than accurate in his observation of the heavens. This, he tells us, is the twelfth comet he has difcovered in thirteen years past.
M. Pingrè has deduced the elements of this comet's orbit from the obfervations of M. Meier, and concludes from them, that it paffed its perihelion the 22d of Nov. 1770; that it reFf fembles
Tembles none of thofe whofe elements are determined; and that it may frequently have paffed in the fun's neighbourhood imperceptible to the northern parts of the earth.
Art. 14. Defeription and Ufe of a new-constructed Equatorial Te lefcope, or portable Obfervatory, made by Mr. Edward Nairne,
We can give our Readers no tolerable idea of this inftrument, without the plate annexed to the article. The construction here defcribed feems to be a valuable improvement.
Art. 43, 44, contain feveral aftronomical and other obfervations made by Mr. Charles Green and Lieutenant James Cook, in their voyage, and during their ftay at King George's (or as it is called by the natives, Otaheite) ifland, in the South Sea.
Art. 45, gives an account of the late tranfit of Venus as it was obferved by M. J. Maurits Molr, in the New Obfervatory at Batavia.
Art. 46. Kepler's Method of computing the Moon's Parallax in Solar Eclipfes, demonfirated and extended to all Degrees of the Moon's Latitude; as aljo to the affigning the Moon's correspondent apparent Diameter: Together with a concife Application of this Form of Calculation to thofe Eclipfes. By the late H. Pemberton, M. D.
This paper contains a very ingenious and accurate folution of an abftrufe problem in aftronomy.
As the moon's parallaxes continually vary during the progrefs of a folar eclipfe, the repeated computation of these renders the calculation of fuch eclipfes very difficult and tedious. The compendium propofed by the famous Kepler, in his Rudolphine Tables, for this purpose, is by no means fo clear and perfect as might be wifhed. To explain and demonftrate his method is the defign of this article.
Art. 49. Defcription of a Method of measuring Differences of right Afcenfion and Declination, with DoLLOND's Micrometer; together with other new Applications of the fame. By the Rev. Nevil Mafkelyne, Aftronomer Royal.
Mr. Dollond's divided object glafs micrometer is, on various accounts, the most convenient and exact inftrument for measuring fmall diftances in the heavens, but is not fo well adapted for meafuring differences of right afcenfion and declination as the common wire micrometer. The Author of this article propofes an eafy and cheap contrivance in order to render it fit for both thefe ufes; and he fubjoins feveral neceffary inftructions for ufing it with accuracy and advantage.
Art. 51. An Account of the going of an Aftronomical Clock. By the Rev. Francis Woolafton, F. R. S.
Art. 53. The Quantity of the Sun's Parallax as deduced from the Obfervations of the Tranfit of VENUS, on June 3, 1769. By Thomas Hornfby, M. A. Savilian Profeffor of Aftronomy in the University of Oxford, and F. R. S.
Mr. Hornby makes the parallax on the 3d of June, by taking the mean refult of feveral obfervations, 8". 65; whence the mean parallax will be found to be 8′′. 78; and if the femidiameter of the earth be fuppofed 3985 English miles, the mean diftance of the earth from the fun will be 93,726,900 English miles and as the relative diftances of the planets are known, their abfolute diftances, and confequently the dimen fions of the folar fyftem, will be, as in the following table;
Relative difiance. Abfolute diftance.
Art. 36. A Difquifion concerning certain Fluents, which are af fignable by the Arcs of the Conic Sections; wherein are investi gated fome new and useful Theorems for computing fuch Fluents. By John Landen, F. R. S.
This difquifition is intended to fupply a defect in theorems of a fimilar nature, propofed and exemplified by Mr. Maclaurin in his treatife of Fluxions, and Mr. D'Alembert, in the Memoirs of the Berlin Academy. As fome of their theorems are partly expreffed by the difference between the arc of an hyperbola and its tangent, and this difference is not directly attainable when fuch arc and its tangent are both, infinite, a computation by fuch theorems muft in all thefe cafes be impracticable. To afcertain 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 fufficient 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 conftruction of logarithms. This article, though small, is an acceptable fpecimen of his unqueftionable abilities in this department of fcience. As it will not admit of any extract or abridgment, we must refer our mathematical Readers to the paper itself.
[To be continued.]
ART. II. Eays on the Spirit of Legislation, in the Encouragement of Agriculture, Population, Manufactures, and Commerce. Containing Obfervations on the political Systems at prefent pursued in various Countries of Europe, for the Advancement of thofe effential Interefts. Tranflated from the original French, which gained the Premiums offered by the Society of Berne in Switzerland, for the best Compofitions on this Subject. 8vo. 5 s. 3 d. Boards. Nicoll. 1772.
THE HE great objects in the domeftic policy of nations are commerce, agriculture, and the arts; and thofe citizens are usefully employed, who endeavour to investigate the proper methods of promoting their advancement. In the prefent pubJication we meet with feveral interefting 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 obferve philofophy and jurifprudence applied to the lower as well as the higher precautions of civil government, we must acknowledge, that in perufing them we were fometimes led to imagine that men of letters were, in many refpects, unequal to the minute inveftigation of the fubjects attempted to be explained in them. They cannot always obtain that information which practice communicates to the artifan, the labourer, and the man of bufinefs. A multitude of facts neceffarily escape their attention; and, in their hafte to form conclufions, they too frequently forget that their premises are imperfect. Imagination and the fpirit of hypothefis are confulted; and the inexperienced Reader miftakes for the acquifitions of experience, the plaufible pictures and inventions of an ingenious mind.
With this caution the prefent publication may be read, both with profit and fatisfaction: even to those in power, to whom it chiefly addrefles itself, it may exhibit views which they might profecute and improve with advantage. It is a melancholy reflection, however, that fuch men are not always folicitous to difcharge, with honour, the important trufts with which they are invefted. It happens frequently that they are unable, and they appear conftantly unwilling, to attend to those minute details which alone can qualify them to act with propriety for the public grandeur and profperity.
The following thoughts on the Freedom of Commerce,' may give our Readers an idea of the fpirit of thefe memoirs :
The eagerness for gain, fo 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 ftates where they multiply ordonnances on commerce, and where they burthen it in a thousand ways, that it flourishes moft. Thefe rules are commonly too varying and changeable;
changeable; they either depend on paffing circumftances, or they are gained by perfons interested in obtaining great profits at the ex pence of all other merchants. Thefe fort of edicts are fubject to contradict themfelves from time to time; and as nothing is fixed, on which they could be founded, they only difconcert the enterprizes of the merchants. Fearing to find themfelves traversed all of a fudden by unforeseen ordonnances, they dare not obey the calls of their genius, and cannot form fucceffive projects. It is better to grant them an honeft liberty, which permits them to hazard attempts for opening new branches of commerce.
It is not that the bridle fhould be entirely relaxed in all points. If they know no other law than their avidity, they will often rifque the prejudice, not only of the commerce, but alfo the agriculture and manufactures of a nation. It is, for example, mischievous to manufactures, and confequently to the commerce of a ftate, to permit them to export and fell to ftrangers the raw materials upon which the arts are employed that are established in the country. England, fo enlightened in its true interefts, knows well how to interdict her merchants exporting wool; and affuredly it is bad politics in Spain, to fell her wool to all other nations who will buy it, rather than work it up herself. It is alfo impoverishing a nation and difcouraging her manufactures, to fuffer them to import all forts of foreign fabrics which might be made at home. Thefe importations become above all burthenfome, when, from neighbouring states, who can furnish immenfe quantities, and who at the fame time, take care not to receive too much in exchange from other nations. In the fame manner it is doing mischief to the agriculture of a country, to leave the merchants mafters of importing at their will foreign corn, which finks that at home to too low a price. For from thence it happens, that the cultivator not being fufficiently indemnified for his care and expences is disheartened, and works with languor. This is a cafe that is often found in the Pays-de-Vaud. When we have grain enough for our own confumption, we are expofed 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 faleable commodities. All thefe examples prove fufficiently, that there are certain reftrictions to which it is proper to fubject merchants. But excepting cafes of this nature we must leave them free.
It is immediately visible, that we ought not to tax the fale of all that is fabricated in a country. When mafters 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 reftrained from felling merchandise, except to a fingle people, and under condition that a certain price is taken for all, as is practifed in a certain ftate. Thefe fort of restrictions are ruinous to a nation. They prevent the fale of merchandise at a juft price, and of profiting by the advantages. The merchants fhould rather be encouraged to carry their correfpondence everywhere. The more markets they find, the more certain means they have of felling Ff3