poles would in time become different; but that both the inner and outer poles having the same power of attraction, would produce the greater or lesser variation as they happened to be at a greater or less distance from each other: this amendment is by some disregarded; by none that we know of adopted; and yet some late experiments, made both by the French and English in different parts of the world, seem now to favour it.

Mr. Halley spared no pains to establish his theory by repeated experiments, and he had so much credit with King William after the revolution, that he obtained the command of the Paramour Pink to complete his observations. In his first attempt, his men proving sickly, and his first lieutenant refusing to obey orders, he returned without effecting any thing; but having suspended his lieutenant, and procured of the government another ship of less burthen to attend him, he took his departure from the coast of England in September 1699, and having traversed the vast Atlantic ocean from one hemisphere to the other, as far as the ice would permit, in his way back he touched at St.Helena, the coast of Brazil, Cape Verd, Barbadoes, Madeira, the Canaries, the coast of Barbary, and in many other latitudes, till at length he arrived in England in 1700, and published a general chart, shewing, at one view, the variation of the compass in all those seas where the English navigators were acquainted; by which he laid a foundation for the discovery of the laws of that variation, so different in different parts of the world.

ac

The method of finding the longitude at sea, by the motions of the moon, was first projected by

Mr. Halley, who took great pains to reduce it to practice; but at the very time when he was most intent upon perfecting his observations, his father's death, and the unexpected reverse of fortune that happened to him on that occasion, put a period to his pleasurable studies, and obliged him to turn his thoughts to the support of a numerous family. His father, who, before the fire of London, was possessed of an estate in houses of 1000l. year, partly by imprudence in marrying a second wife, and partly by misfortunes, died insolvent.

Mr. Halley, disappointed of his paternal inheritance, began to think seriously of converting that knowledge and experience, which had cost him so much labour and study, to his own more immediate advantage, and it was fortunate for him that he made himself acceptable to Sir Isaac Newton, by applying to him for the solution of a problem which had baffled the skill of Sir Christopher Wren and Mr. Hook, who were at that time celebrated all over Europe for their great skill in the mechanical powers, and for their knowledge in the sciences; which Mr. Newton answered without hesitation. Mr. Newton was then at Cambridge, and employed in his Principia, a work now so well known, that it is scarce necessary to mention more of the title: he was pleased with the application made to him by Halley, and ever after conceived a friendship for him.

In the interval between his first voyage and his father's death, Mr. Halley had made many useful discoveries, which are omitted in their place, particularly a method of measuring the elevation of very

high mountains and other eminences, by the barometer, and the physical causes of the trade winds and monsoons, which he illustrated by à chart, representing their direction, wherever they blow, in every part of the globe; he accounted also for the equality of height in the Mediterranean sea, notwithstanding the continual accumulation of waters to it by nine large rivers, and the constant setting in of the current in the mouth of the Straits, without any visible discharge by any canal whatever.

We should likewise have taken notice, that Mr. Halley was chosen assistant secretary to the royal society, on the resignation of Dr. Musgrave, in 1685; and in 1691 he was disappointed of the Savi'ian professorship at Oxford, by the jealousy of Mr. Flamstead, who took it in his head that he had suffered in estimation of Sir Isaac Newton, by Mr. Halley's growing friendship with that great man.

Soon after this mortification, he published his tables, shewing the value of annuities for lives, calculated from the bills of mortality at Breslau, in Silesia; and the same year came out his famous universal theories for finding the foci of optic glasses.

In 1695 he resigned the office of assistant secretary, and was appointedcromptroller of the Mint at Chester in 1696. Here his active genius gave no way to idleness. He employed himself during the two years that this subsisted, in philosophical experiments and physical disquisitions; and his hypothesis concerning the cause of the universal deluge by the approach of a comet, which Mr. Whiston adopted

in his new theory of the earth, was about this time produced.

We have already related the success of his voyages in the Paramour Pink, before which he was employed by King James II. to observe the course of the tides in every part of the British channel, and to take the latitude and longitude of the principal headlands, which he performed with great accuracy, and in 1702 published a large map of the British channel. The same year he was sent by Queen Anne to the Emperor to view the coast of Dalmatia, and to construct a safe harbour for shipping, as commodious as possible for the trade of the Adriatic sea; but some objections being made to this project by the Dutch, the execu tion of the design was deferred, and Mr. Halley returned home, with very singular marks, however, of the Emperor's favour, who gave him from his own finger a ring of considerable value. Not long after his arrival in England he was again sent upon the same errand, and in his way to the Emperor's court, had the honour to sup with his late majesty King George I. at his palace of Herenhausen, where he was entertained with great marks of respect. On his arrival at Vienna he was again presented to the Emperor, who ordered his chief engineer to attend him to Istria, where they added some new works to the fortifications of Trieste, the port of Boccari being found capable of receiving ships of all burdens with the greatest safety.

In the year 1703, just before the great storm, he returned to England, and Dr. Wallis being then dead, he was now appointed Savilian Professor at Oxford without opposition, and was complimented

with

with the degree of doctor of laws by that university. Here he was employed in translating, and revising some ancient authors on the abstruser parts of mathematics, particularly Apollonius de sectione rationis and Serenus's Conics.

In 1713 he succeeded Sir Hans Sloane in the post of secretary to the royal society; and, as perfecting the theory of the moon's motion was always uppermost in his thoughts, tho' prevented from it by the multiplicity of public business, he now applied all his leisure hours to that subject, and in 1715 he was able by that means to predict the central eclipse of the sun to a few minutes, and to project a map of the extent of the moon's shadow to such a degree of exactness, as advanced his reputation in that article of astronomy beyond the reach of party opposition. On the death of Mr. Flanistead in 1719, he was appointed to succeed him. By this new employment he was not only enabled to pursue his favourite studies without interruption, but he was also possessed of a competency to support his family without that anxiety of mind, to which, by the uncertainty of his income, he had long been subject.

When he was advanced toGreenwich he was in the 64th year of his age; notwithstanding which he attended the telescope with uncommon application for 18 years without any assistance: in all which time a meridian view of the moon scarce ever escaped him whenever the disposition of the heavens would permit. In 1721 he resigned the post of secretary to the royal society, that nothing might interrupt the business of his new employment. Upon the accession of his present

majesty to the throne, the late Queen Caroline made a visit to the royal observatory, and being highly delighted with the polite reception she met with, was pleased to add to his salary the half-pay of a captain of the navy, to which, by his former commission, he had an undoubted claim; but he declined the offer that was made him of being appointed mathematical preceptor to the Duke of Cumberland, as incompatible with his years, and the ordinary attendance of his duty at Greenwich.

In August 1729 he was admitted a foreign member of the academy of sciences at Paris, in the room of Signior Branchini; and in 1731 he published a proposal for finding the longitude at sea within a degree, having perfected his tables for one whole period of the moon's apogæum, in which time he had observed the right ascension of the moon, at her transit over the meridian near 1500 times, a number not less than Tycho Brahe, Hevelius, and Flamstead's added together.

In 1737 he was seized with a paralytic disorder in his right hand, an attack the more alarming as it was the first he had ever felt upon his constitution; which gradually increasing, he came at length to be wholly supported by such cordials as were ordered by his physicians, till being tired with these, he asked for a glass of wine, and having drank it, expired as he sat in his chair, on the 14th of January, and in the 86th year of his age, without a groan. He was interred at Lee, near Greenwich, in the same grave with his beloved consort. And as he was a member whose name reflected honour upon

the

the Royal Academy of Sciences at Paris, Mr. Mairan, according to custom, pronounced his eulogy, from which these further particus lars are extracted. "He, says Mairan, possessed all the qualifications necessary to please princes who are desirous of instruction, great extent of knowledge, and a constant presence of mind; his answers were ready, and at the same time pertinent, judicious, polite, and sincere. When Peter the Great, Emperor of Russia, came into England, he sent for Mr. Halley, and found him equal to the great character he had heard of him. He asked him many qustions concerning the fleet he intended to build, the sciences and arts which he wished to introduce into his dominions, and a thousand other subjects which his unbounded curiosity suggested; he was so well satisfied with Mr. Halley's answers, and so pleased with his conversation, that he admitted him familiarly to his table, and ranked him among the number of his friends, a term which we may venture to use with respect to a prince of his character; a prince truly great, in making no distinctions of men but that of their merit. But Mr. Halley, continues this writer, possessed still more of the qualifications necessary to obtain him the love of his equals: in the first place he loved them; naturally of an ardent and glowing temper, he appeared animated in their presence with a generous warmth, which the pleasure alone of seeing them seemed to inspire; he was open and punctual in his dealings, candid in his judgment, uniform and blameless in his man, ners, sweet and affable, always ready to communicate, and disinVOL. II.

terested. He opened a way to wealth by all that he effected for the improvement of navigation; to the glory of which he has added, that of having done nothing to enrich himself: he lived and died in that mediocrity so much extolled by philosophers, the free choice of which implies a great degree both of virtue and wisdom. The only mere lucrative place he ever had, was that in the mint at Chester, which soon determined, and he never desired another. He was generous, and his generosity exerted itself even at the expence of vanity, from which the learned are no more exempted than other men, and which perhaps they more frequently betray. I am furnished, proceeds Mr. Mairan, with an instance of this, by a letter which accidentally came into my hands about six years ago, written by him to an author whom he knew only by reputation. Mr. Halley, in this letter, with equal sagacity and politeness, points out an error in a very critical calculation which that author had fallen into, in treating on the principal point of a question in astronomy and physics. It must not however be concealed, that Mr. Halley never published that letter, although it would certainly have done him honour; but we must not too particularly reveal a secret, from the concealment of which he derives still more.

The reputation of others gave him no uneasiness,a restless jealousy and anxious emulation were strangers to his breast. He was equally ignorant of those extravagant prejudices in favour of one nation, which are injurous to all others. The friend, countryman, and disciple of Newton, he spoke of Des

U

Cartes

Cartes with respect; and successor to Dr. Wallis, he did justice to the merit of our ancient geometricians. To conclude, these uncommon and valuable qualifications were tempered in Mr. Halley with a vein of gaiety and good humour which neither his abstracted speculations, the infirmities of old age, nor the palsy itself, which seized him some years before his death, could impair: and this happy disposition, the gift of nature, was the more perfect, as it was still attendant upon that peace of mind, which is the noblest endowment of virtue." Since his death, his long expected tables of the sun and planets were published in 1752, in 4to. with this title, Astronomical Tables, with precepts both English and Latin, for computing the places of the sun, moon, planets, und comets.

An account of Baron Holberg, extracted from An enquiry into the present state of polite learning in Europe.

THE

HE history of polite learning in Denmark, may be comprized in the life of one single man: it rose and fell with the late famous Baron Holberg. This was, perhaps, one of the most extraordinary personages that has done honour to the present century. His being the son of a private centinel, did not abate the ardour of his ambition; for he learned to read, though without a master. Upon the death of his father, being Jeff entirely destitute, he was involved in all that distress, which is common among the poor, and of which the great have scarce any

idea. However, tho' only a boy of nine years old, he still persisted in pursuing his studies, travelled about from school to school, and begged his learning and his bread. When at the age of seventeen, instead of applying himself to any of the lower occupations, which seem best adapted to such circumstances, he was resolved to travel for improvement from Norway, the place of his birth, to Copenhagen, the capital city of Denmark. He lived here by teaching French, at the same time avoiding no opportunity of improvement, that his scanty funds could permit. But his ambition was not to be restrained, or his thirst of knowledge satisfied, until he had seen the world. Without money, recommendations, or friends, he undertook to set out upon his travels, and make the tour of Europe on foot. A good voice, and a trifling skill in music, were the only finances he had to support an undertaking so extensive; so he travelled by day, and at night sung at the doors of peasants houses, to get himself a lodging. In this manner, young Holberg passed through France, Germany, and Holland, and, coming over to England, took up his residence for two years in the university of Oxford. Here he subsisted by teaching French and music, and wrote his Universal History, his earliest, but worst performance. Furnished with all the learning' of Europe, he at last thought proper to return to Copenhagen, where his ingenious productions quickly gained him that favour he deserved. He composed not less than eighteen comedies; those in his own language are said to excel, and those which are wrote in French have peculiar merit. He

was