The Schehallien experiment was carried on under many difficulties and privations; and its successful result places its author in the list of those who first opened the road to the determination of a fundamental element of the solar system. But brilliant as it must appear, it is by no means the most useful of Maskelyne's labours. Excepting Bradley, he may almost be called the first who systematically directed his efforts to the attainment of the minutest accuracy in astronomical observation. His celebrated Catalogue, A.D. 1790, consisted only of thirty-six of the principal stars, but the places of these, especially in right ascension, were determined with a degree of precision which was then believed to be hardly attainable. The means by which he accomplished his objects, such as taking the nearest tenth of a second instead of the nearest second, or half second, of time in his transit observations, the practice of uniformly observing all the wires of the instrument, instead of one; the introduction of the movable eye-piece, by which the several wires could all be viewed directly, instead of obliquely, and many little things of the kind, are the indications of a man who was familiar above his contemporaries with the sources of error, and who had formed at once a bold estimate of the extent to which they might be avoided, and a correct view of the means of doing it. It is difficult to say what portion of the present improved spirit of observation in these points may be attributed to Maskelyne, but it certainly was not small. Delambre, who knew at least as well as any man of his time what had been done and was doing, and who was never profuse of praise, as his History of Astronomy' amply demonstrates, pays him the following compliment in the memoir which he contributed to the Biographie Universelle Maskelyne était en correspondance avec tous les astronomes de l'Europe, qu'il considé

rait comme ses frères, et qui, de leur côté, le respectaient comme un doyen, dont les travaux leur avaient été éminemment utiles."

We have spoken, in the life of Harrison, of the controversy about the merits of the time-piece of the latter. As Astronomer Royal, Maskelyne was the official investigator of the rates of those instruments, and both in the case of Harrison, and in that of Mudge, his decisions underwent printed attacks, which he answered. Without entering into the merits of these questions, since all the grave accusations which were brought against him have fallen harmless, we shall only state, that Maskelyne's answers are full of documents, and free from passion; both very favourable symptoms.

Dr. Maskelyne held church preferment from his college, and was besides in possession of an easy fortune. He died February 9, 1811, leaving behind him an unblemished personal reputation, and a character for scientific utility of the first order. He left behind him much evidence of his utility in the labours and character of the assistants whom he formed; all of whom, says Lalande, were useful astronomers. The late Dr. Brinkley, Bishop of Cloyne, who added the reputation of a distinguished mathematician to that of an eminent observer, was for some time one of his pupils in the practical part of the science.

JOSEPH LOUIS LAGRANGE was born at Turin, January 25th, 1736. His great-grandfather was a Frenchman, who entered into the service of the then Duke of Savoy; and from this circumstance, as well as his subsequent settlement in France, and his always writing in their language, the French claim him as their countryman; an honour which the Italians are far from conceding to them.

The father of Lagrange, luckily perhaps for the fame of his son, was ruined by some unfortunate speculation. The latter used to say, that had he possessed fortune, he should probably never have turned his attention to the science in which he excelled. He was placed at the College of Turin, and applied himself diligently and with enthusiasm to classical lite

rature, showing no taste at first for mathematics. In about a year he began to attend to the geometry of the ancients. A memoir of Halley in the Philosophical Transactions, on the superiority of modern analysis, produced consequences of which the author little dreamed. Lagrange met with it, before his views upon the subject had settled; and immediately, being then only seventeen years old, applied himself to the study of the modern mathematics. Before this change in his studies, according to Delambre*, after it, according to others, but certainly while very young, he was elected professor at the Royal School of Artillery at Turin. We may best convey some notion of his early proficiency, by stating without detail, that at the age of twenty-three we find him—the founder of an Academy of Sciences at Turin, whose volumes. yield in interest to none, and owe that interest principally to his productions, a member of the Academy of Sciences at Berlin, an honour obtained through the medium of Euler, who shortly after announced him to Frederic of Prussia as the fittest man in Europe to succeed himself,-and settling, finally, a most intricate question† of mathematics, which had given rise to long discussions between Euier and D'Alembert, then perhaps the two first mathematicians in Europe. He had previously extended the method of Euler for the solution of what are called isoperimetrical problems, and laid the foundation for the Calculus of Variations, the most decided advance, in our opinion, which any one has made since the death of Newton.

In 1764 he gained the prize proposed by the Academy of Sciences for an Essay on the Libration of the

*Eloge de Lagrange, Mémoires de l'Institut. 1812.

The admissibility of discontinuous functions into the integrals of partial differential equations.

Moon; and in 1766, that for an Essay on the Theory of the Satellites of Jupiter. In the former of these we find him, for the first time, using the principle of virtual velocities, which had hitherto remained almost a barren truth, but which he afterwards made, in conjunction with the principle known after the name of D'Alembert, the foundation of the whole of mechanical science.

In 1766 Euler, intending to return to St. Petersburg, resigned the situation which he held at the Court of Berlin, that of director of the physico-mathematical class of the Academy of Sciences. Frederic offered this place to D'Alembert, who refused it for himself, but joined with Euler in recommending Lagrange. The King of Prussia acceded to their suggestion, and Lagrange was invited to establish himself at Berlin, with a salary equivalent to 6000 francs.

Lagrange remained at Berlin till after the death of Frederic. He here married a lady who was related to him, and who came from Turin at his request. She died after a lingering illness of several years, marked by the most unceasing attention on the part of her husband, who abandoned his pursuits to devote himself entirely to her during her illness. Nevertheless the period of his sojourn at Berlin is perhaps. the brightest of a life, most years of which, from the age of eighteen to that of seventy, were sufficient to ensure a lasting reputation. He here laid the foundation of his Theory of Functions, of his general method for determining the secular variations of the planetary orbits; and here he wrote his Mécanique Analytique.

At the death of Frederic, he found that science was no longer treated with the same respect at the Court of Berlin. He had found from the commencement of his stay there that foreigners were looked upon with dislike, and his spirits had not recovered the loss of his wife. Many advantageous offers were