book

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imagine that men of learning and genius will be altogether fatisfied with fuch kind of fecond hand performances.-But let us see what the compilers themselves have to fay in praife of their own undertaking, in the Preface; where we are told, that

"The NOTES, EXPLICATIONS, and OBSERVATIONS, will be fuch as will be of real SERVICE, thofe of lefs USE, with which many commentators do too much abound, and which would fwell the work to too great a bulk, will be omitted: However, all important matters will be fully treated of;-yet-the whole work will be brought into as narrow a Compass as the nature of the defign (to be well executed) will admit of.'- -Our readers will make their own remarks upon the style, and manner of pointing (which is exactly followed) both in this quotation, and the title of the book.

The prefent volume begins with Genefis, and ends with the book of Esther: fo that the narrow compafs into which the whole work is promised to be brought, will probably be three volumes in folio, at the leaft.-The text and notes are all along intermixt; which appears to us a much less eligible method of difpofition, than it would have been to have placed the former at the top, andthe latter at the bottom of the page.

As a fpecimen, we fhall give the laft chapter of the book of Efther.

1. And the king Ahafuerus laid a tribute upon the land, and upon the ifles of the fea.

Laid a tribute upon the land, and upon the ifles of the fea.] • Having occafion for money, he laid a new tax upon all his provinces, both in the continent (as we freak) and in the ifles of the Egean fea, belonging to his dominions.'

2. And all the acts of his power, and of his might, and the declaration of the greatness of Mordecai, whereunto the king advanced him, are they not written in the book of the chronicles of the kings of Media and Perfia?

Thefe words fignify, that as this king did great things, fo they were to be afcribed very much to the management of Mordecai, after he was advanced to the highest authority in the kingdom. But it was not the defign of the author of this hiftory, to relate fuch things; for which he refers to the publick records of the kingdom, which were kept in fome part of the king's houfe (as appears from ch. vi. 1.) and were extant in thofe days, when this book was written.'

3. For Mordecai the Jew was next unto king Ahafuerus, and great among the Jews, and accepted of the multitude of

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his brethren, feeking the wealth of his people, and fpeaking peace to all his feed.

And accepted of the multitude of his brethren.] His greatnefs did not make him forget his brethren: by whom he was highly eflcemed, and much honoured by every one of them.'

And Speaking peace to all his feed.] Advifing and promoting whatfoever was for their advantage; and fpeaking ftill to the king for that which might tend to the happiness and profperity of his nation, which he advanced to the utmost of his power; treating even the pooreft of his countrymen with affability, and not difdaining to fpeak familiarly and kindly with any of them; which fhews him to be a man of a noble and amiable difpofition, who was not puffed up with fuch an unexpected rife of his condition, which redounds greatly to his praise.

That which is faid at the end of this chapter, that Mordecai procured the good of his nation, and fought the profperity of his people, is a leflon to great men, and thofe that are in credit and authority, that if God hath raifed them, the beft ufe they can make of their authority is, to employ it to fupport the innocent, advance the interefls of religion, and promote the glory of God.'

N. B. This Work is publishing in weekly Numbers, at 6d. each.

New Principles of Geography, and Navigation. In two parts. Part I. containing, The theory of the true figure and dimenfions of the earth, deduced from actual menjuration, and applied to a just conftruction of maps and charts, for land and fea ufe. The whole exemplified in a new geographical chart for Europe, and a large fea chart to feventy degrees of latitude. Both which are adapted to the spheroidical figure of the earth, and the degrees in each are divided into minutes, with a folution of all the cafes of failing on this new ecliptic chart. Part ll. containing a table of meridional parts, calculated for the Spheroid to every minute of latitude, from the measure of a degree at the equator, by don George Juan, and don Antoine de Ulloa, with a folution of the feveral cafes of failing by it. Also new astronomical principles of navigation, and an improved mechanical theory of working a fhip, with a table of the fun's declination and place in the ecliptic. By Benjamin Martin. Folio. 10s. 6d. Newbery.

ATHEMATICIANS, from the earlieft ages, con

Midered the earth as a phere, and on this fuppofition

founded their principles of geography and navigation. But as it was alfo ablolutely neceflary to determine the magnitude of the earth, feveral attempts to anfwer fo valuable a purpofe were

made

made in different ages and with different degrees of accuracy; till at length M. Piccard, purfuant to an order of Lewis XIV. feemed to have put a ftop to all further enquiries of this kind, by his accurate menfuration of a degree of the meridian.

But in the year 1672 M. Richer, in making aftronomical obfervations at Cayenne, the capital of an ifland near the coaft of South-America, in about 59 N. latitude, found that his pendulum clock, which had been carefully regulated at Paris, loft every day two minutes 28 feconds. At his return he published an account of this phenomenon, which he confidered as very important, and worthy the difquifition of philofophers; and as it appeared at a time when the greateft ornaments of mathematical learning flourished, it did not long wait for a fatiffactory folution. The penetration of Sir Ifaac Newton foon discovered that it was owing to a diminution of the preflure of gravity; that Cayenne was therefore farther from the center of the earth, than Paris; and, confequently, that the earth was an oblate spheroid and, from a very fubtle theory, he found, that the axis of the earth was to the diameter of the equator as 229

to 230.

And here perhaps the enquiry might have terminated, had not Caffini, from repeated menfurations, in different places, with different inftruments, and by different methods, declared in a treatile published in the year 1718, that the earth, inflead of being an oblate, was a prolate ipheroid, the length of the axis being 6579368 toifes, and that of the equatorial diameter 6510796 toifes.

As these measures were fo contrary to the figure of the earth, refulting from the experiments of M. Richer, and the laws of hydroftatics; and as, at the fame time, the decifion of this point was of the utmost importance; the king of France fent, in the year 1736, certain mathematicians to the equator, and others to the arctic circle, to measure the length of a degree of the meridian at thofe places, in order to determine the true figure and dimenfions of the earth.

The mathematicians who went to the north, at the head of whom was the celebrated Maupertuis, foon performed their tafk, and found that the length of a degree under the arctic circle contained 57437,9 toifes, about 1000 toifes longer than it ought to be according to Caffini's table, which fufficiently proved the earth to be an oblate fpheroid, and confirmed the theory of Sir Ifaac Newton.

From this menfuration, and the length of a degree accurate ly meatured in France, Mr. Martin has determined the figure,

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&c. of the earth, fhewn the true principles of conftructing geographical maps, and the method of folving the various cafes of navigation, by a new fea chart, conftructed from thefe principles; as had before been done by feveral writers, particularly the Rev. Mr. Murdock; tho' Mr. Martin's are the first charts we have feen of this contruction, alapted to the practice of navigation; and by dividing the degrees of longitude and latitude diagonally, are rendered far more accurate than any yet published.

The difference refulting from two folutions of the fame queftion according to Mercator's chart, and the new one of Mr. Martin's, is very confiderable: for if a fhip fails from a port in the lat. of 38° to another in 5, and the difference of longitude 43°, her courfe will be 49° 58', and her diftance 3078 miles, according to Mercator's chart; but, by Mr. Martin's, the courfe will be 50° 29', and the datence only 30:9 miles. Thus the error in the courfe is 31', and that in the distance 19 miles.

But as thefe conclufions followed from meníurations taken in France and Lapland, mathematicians waited with impatience the refult of the operations in Peru: and in the year 1748 Don George Juan and Don Antonio de Ulloa, who joined the mathematicians fent from France, and affifted in measuring a degree at the equator, publifhed, at Madrid, the refult of their operations. In the year 1744, an account also appeared by the French Mathematicians, in the memoirs of the Royal Academy of Sciences at Paris. Meff. de la Condamine and Bouguer likewife obliged the public with accounts of this noble undertaking, which had engaged the attention of all Europe.

This Menfuration confirmed the opinion of Sir Ifaac Newton, that the earth was an oblate fpheroid; but at the fame time proved that its dimenfions were very different from those refulting from the menfurations made in Lapland and France; for according to the latter the length of a degree at the equator will be only 65600, whereas it was found by menfuration to be 56767,788 toiles; fo that the figure of the earth, according to this menfuration, approaches much nearer to a fphere, than was thought from thofe made in the north, and is not very different from that refulting from Sir Ifaac's theory. It will therefore follow that the furtace of the earth is not that of a perfect fpheroid, or that it is impoffible to determine its true dimenfions by actual menfuration. For it appears from the accounts published, that all of them were performed with the greatest

care

care and accuracy; and, confequently, that there is not the leaft reafon for preferring either of them to the other.

Now, if we folve the problem mentioned above, by Don Juan's meridional parts, which Mr. Martin has inferted in this performance, the fhip's courfe will be 50° 8', and her distance 3071; differing from the folution by Mercator's chart g' in the courfe, and 7 miles in the distance. But the error in the course is of no confequence at all, it being abfolutély impoffible to fteer a fhip to a degree, much lefs to nine minutes; and the 7 miles, in fo large a diftance, is inconfiderable; especially if we fubdivide it into twenty days work, and confider the many incidents of unknown currents, feas running either with or against the fhip, lee-way, and innumerable others, which render it impoffible to keep an accurate account of a ship's way.

Nor can we ever hope to fee the art of navigation brought to perfection, till the latitudes and longitudes of places are more accurately determined than they are at prefent; for every perfon who has been converfant in the practice of navigation, well knows, from experience, that the furer he is of the latitude and longitude of his fhip, the more certainly will he mifs the intended port, a very few only excepted, whofe longitudes and latitudes are determined to the neceffary exactness. The firft thing therefore neceflary to be done, is to fettle the latitudes and longitudes of our fea coafts, and from thence to conftruct accurate maps, according to the true figure of the earth: for it is of no confequence to endeavour to correct minute errors, while others of the greatest magnitude are continued. There is, however, but very little hopes of this being effected; the failors are too tenacious of old cuftoms to affift in improving their art; and it is only from those who vifit the different parts of the globe, that the neceffary obfervations can be expected.

This cannot, however, be imputed to the mathematicians. They have done all in their power to improve the art of navigation; and the work before us is a proof, among innumerable others, that calculations, however laborious, are not fufficient to deter them from performing whatever has a tendency to improve the ufeful branches of fcience.