arranged facts, or what the author believed to be such, is in the main rather disquisitional and theoretic than historical in the proper sense.

POLITICAL ECONOMY; THEOLOGY; CRITICISM AND BELLES LETtres.

Besides his metaphysical and historical works, upon which his fame principally rests, the penetrating and original genius of Hume also distinguished itself in another field, that of economical speculation, which had for more than a century before his time to some extent engaged the attention of inquirers in this country. There are many ingenious views upon this subject scattered up and down in his Political Discourses, and his Moral and Political Essays. Other contributions, not without value, to the science of political economy, for which we are indebted to the middle of the last century, are the Rev. R. Wallace's Essay on the Numbers of Mankind, published at Edinburgh in 1753: and Sir James Steuart's Inquiry into the Principles of Political Economy, which appeared in 1767. But these and all other preceding works on the subject have been thrown into the shade by Adam Smith's celebrated Inquiry into the Nature and Causes of the Wealth of Nations, which, after having been long expected, was at last given to the world in the beginning of the year 1776. It is interesting to learn that this crowning performance of his friend was read by Hume, who died before the close of the year in which it was published; a letter of his to Smith is preserved, in which, after congratulating him warmly on having acquitted himself so as to relieve the anxiety and fulfil the hopes of his friends, he ends by saying, "If you were here at my fireside, I should dispute some of your principles. . . . But these, and a hundred other points, are fit only to be discussed in conversation. I hope it will be soon, for I am in a very bad state of health, and cannot afford a long delay." Smith survived till July, 1790.

A few other names, more or less distinguished in the literature of this time, we must content ourselves with merely mentioningin theology, Warburton, Lowth, Horsley, Jortin, Madan, Gerard, Blair, Geddes, Lardner, Priestley; in critical and grammatical disquisition, Harris, Monboddo, Kames, Blair, Jones; in antiquarian research, Walpole, Hawkins, Burney,

Chandler, Barrington, Steevens, Pegge, Farmer, Vallancey, Grose, Gough; in the department of the belles lettres and miscellaneous speculation, Chesterfield, Hawkesworth, Brown, Jenyns, Bryant, Hurd, Melmoth, Potter, Francklin, &c.

PROGRESS OF SCIENCE.

The last notices given under that head brought down our sketch of the progress of the mathematical and physical sciences to the death of Flamsteed in 1719. The successor of Flamsteed, as astronomer royal, was Edmund Halley, who was then in his sixty-fourth year, and who held the appointment till his death in 1742, at the age of eighty-six. "Among the Englishmen of his day," says the writer of his life in the Penny Cyclopædia, "Halley stands second only to Newton, and probably for many years after the publication of the Principia he was the only one who both could and would rightly appreciate the character and coming utility of that memorable work. His own attention was too much divided to permit of his being the mathematician which he might have been; but nevertheless his papers on pure mathematics show a genius of the same order of power, though of much less fertility, with that of John Bernouilli.” Besides numerous papers in the Philosophical Transactions, Halley is the author of a Catalogue of the Southern Stars (Catalogus Stellarum Australium, sive Supplementum Catalogi Tychonici), published in 1679, being the result of his observations made at St. Helena, where he had resided the two preceding years; and of editions of the treatise of Apollonius De Rationis Sectione (from the Arabic), and of the same ancient geometrician's Conic Sections (partly from the Arabic), the former of which was published at Oxford in 1706, the latter in 1710. Halley did not himself understand Arabic, but he was able both to restore what was lost in these works and in many cases to suggest the true meaning and emendation of the text where it was corrupted, merely by his geometrical ingenuity and profound knowledge of their subjects. Besides other astronomical labours, Halley is famous for having been the first person to predict the return of a comet, that known by his name, which he first saw at Paris in Penny Cyclopædia, xii. 21.

December 1680, and which actually reappeared, as he had calculated that it would, in 1758 and 1835. He also suggested the observation of the transit of Venus, with the view of determining the sun's parallax, which was accomplished at St. Helena, by Dr. Maskelyne, in 1761. Out of the province of astronomy he contributed to the progress of science by his construction of the first tables of mortality (from observations made at Breslau), by his improvements in the diving-bell, and by his speculations on the variation of the compass, the theory of the trade winds, and other subjects.

"'*

The third astronomer royal was James Bradley-"the first, perhaps, of all astronomers," as he is called by the writer of his life in the Penny Cyclopædia, "in the union of theoretical sagacity with practical excellence." Bradley, who was born in 1693, had already in 1728 made his great discovery of the aberration of light, or the apparent alteration in the place of a star arising in part from the motion of light, in part from the change of position in the spectator occasioned by the motion of the earth; "the greatest discovery," says the writer just quoted, "of a man who has, more than any other, contributed to render a single observation of a star correct enough for the purposes of astronomy," and "the first positively direct and unanswerable proof of the earth's motion." Bradley, whom Newton had declared the best astronomer in Europe, held the office of astronomer royal from 1742 till his death in 1762. Besides an immense mass of observations of unprecedented accuracy (which have been published by the University of Oxford in two volumes, 1798–1805), he made in 1747 his second great discovery of the nutation of the earth's axis, that is, of the fact that the curve in which the pole of the equator moves round the pole of the ecliptic is not that of a plain but of a waving or tremulous circle, somewhat like the rim of a milled coin. One of the subjects that occupied the attention of this distinguished astronomer was the introduction of the new style, which was effected by act of parliament in 1751. "Bradley," says his biographer in the Penny Cyclopædia,

appears to have had some share in drawing up the necessary tables, as well as in aiding Lord Macclesfield, his early friend, and the seconder of the measure in the House of Lords, and Mr. Pelham, then minister, with his advice on the subject.

* Penny Cyclopædia, v. 320.

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But this procured him some unpopularity, for the common people of all ranks imagined that the alteration was equivalent to robbing them of eleven days of their natural lives, and called Bradley's subsequent illness and decline a judgment of heaven." This," adds the learned writer, was, as far as we know, the last expiring manifestation of a belief in the wickedness of altering the time of religious anniversaries, which had disturbed the world more or less, and at different periods, for fourteen hundred years. But, if the people believed that the change of style had actually shortened their lives, they had more serious cause for alarm than the zealots of orthodoxy in former times, who made themselves unhappy about the notion of merely celebrating Easter on the wrong day.

In the earlier part of the eighteenth century, we ought not to omit to mention, was invented the ingenious and valuable instrument called Hadley's Quadrant (since improved into a sextant, and still more recently into an entire circle), either by John Hadley, who was a fellow of the Royal Society, and who gave an account of it in the Philosophical Transactions for 1731, or by Thomas Godfrey, a glazier in Philadelphia, who is generally believed to have been in possession of it a year before the date of Hadley's communication. But it appears that a similar instrument had been described to Dr. Halley by Newton, some time before his death in 1727. And this age is also marked in the history of optics and astronomical observation by the important correction of the Newtonian views as to the dispersion of refracted light, of which the honour belongs to John Dollond, and by the invention of the Achromatic Telescope, with which that sagacious and philosophical experimentalist followed up his discovery. Dollond's account of his Experiments concerning the Different Refrangibility of Light appeared in the Philosophical Transactions in 1758; and his achromatic object-glass was contrived the same year.

Of a few other distinguished British mathematicians belonging to the middle portion of the last century the most eminent was Colin Maclaurin, the successor of James Gregory in the mathematical chair at Edinburgh, who was born in 1698, and died in 1746. Maclaurin's principal works are his Geometria Organica (a treatise on curves), published in 1720; his admirable Treatise on Fluxions, 1742; and his Treatise on Algebra, 1748. Another Penny Cyclopædia, v. 321.

very able performance printed after his death is his Account of Sir Isaac Newton's Philosophical Discoveries, which also appeared at London in 1748. All Maclaurin's works are distinguished by profoundness and solidity united with elegance, and often by originality in the method of exposition, or novelty in the application of principles. His countryman and contemporary, Dr. Robert Simson, professor of mathematics at Glasgow (b. 1687, d. 1768), was also a most learned and able geometrician: he is the author of a restoration of the Loci of Apollonius, and of an English translation of Euclid, which continued down to our own day in common use as an elementary book both in Scotland and England. Along with these may be mentioned James Stirling, the author of a Latin treatise published in 1717, on what are called lines of the third order, and a treatise on fluxions, entitled Methodus Differentialis, 1730. William Emerson, a mathematician and mechanist of great talent, whose death did not take place till 1782, when he had reached his eighty-first year, is the author of a series of works on fluxions, trigonometry, mechanics, navigation, algebra, optics, astronomy, geography, dialing, &c. His manner of writing is singularly uncouth; but his works often exhibit much scientific elegance, as well as considerable invention. Another author of a remarkable series of mathematical works, of this date, is the self-taught genius, Thomas Simpson, who was born at Market Bosworth, in the humblest rank of life, in 1710, worked at his trade of a weaver till he was seven-and-twenty, and then suddenly came forth as one of the most acute and well-furnished mathematical writers of the day. A Treatise on Fluxions, another on the Nature and Laws of Chance, a quarto volume of Essays on subjects in speculative and mixed mathematics, a work on the doctrine of Annuities and Reversion, a second volume of Mathematical Dissertations, a treatise on Algebra, another on Elementary Geometry, another on Trigonometry, plane and spherical, a new work on the doctrine and application of Fluxions, a volume of Exercises for young proficients in Mathematics, and a volume of Miscellaneous Tracts, were all produced by Simpson in the twenty years between 1737 and 1757. And he also furnished several papers to the Philosophical Transactions, and edited for some years the mathematical annual called the Ladies' Diary. He died in 1761. In the same year with Simpson was born in Banffshire, in Scotland, James Ferguson, who was the son of a