honourably filled it for upwards of 34 years. On his retirement, the Board of Ordnance assigned him a pension of £500 per annum, in testimony of regard for his long and faithful services: and, as he had previously acquired a very handsome fortune, by the profits upon his laudable exertions, he fixed his abode in Bedford Row, London, where, until the time of his decease, he enjoyed his otium cum dignitate, heightened by the sweets of domestic intercourse, and the occasional society of his friends. Occasionally, too, during the first ten years of his retirement from Woolwich, he conducted the half-yearly examinations at the Royal Military Academy, by the results of which the new commissions in the Royal Artillery and Engineers were determined, as also the examinations at the East India College at Addiscombe; but these the infirmities of his advanced age compelled him to relinquish.

In the year 1812 Dr. Hutton published, in three volumes octavo, a collection, entitled "Tracts on Mathematical and Philosophical Subjects; comprising, among numerous important Articles, the Theory of Bridges, with several Plans of recent Improvement: also, the Results of numerous Experiments on the Force of Gunpowder, with Applications to the Modern Practice of Artillery." These volumes contain, with improvements and corrections, several of the detached papers and essays of which mention has already been made: they also include the History of the Writings and Investigations in Trigonometry and Logarithms, as published in the Introduction to the Doctor's Mathematical Tables, and the History of the Discoveries and Inventions in Algebra, which was first published under the word ALGEBRA, in the Doctor's Mathematical and Philosophical Dictionary. But several of these "Tracts" are altogether new, and contain a methodical and perspicuous account of Dr. Hutton's valuable experiments on gunnery, and with the whirling machine; together with a copious exposition and application of the principal scientific deductions which have been made from these numerous and cautious experiments.

Such is the usual imperfection of human character, that habits of meditation and research, and those which characterize the man of active life, are very seldom united in one individual; and they who adequately appreciate the time and study necessary to produce such numerous, varied, and important works, as have here been spoken of, will scarcely conjecture that these opposite habits united in the person of Dr. Hutton. The truth, however, is, that notwithstanding the incessant vigilance with which he discharged his duties as a Professor of Mathematics at the Woolwich Institution, the time devoted to his numerous publications, and to his experiments on gunnery and the resistance of the air, he still found leisure and inclination to project and to effect improvements of a very different kind. The state of his health, about twelve years after the commencement of his duties at Woolwich, became so precarious, that the Mastergeneral of the Ordnance permitted him to reside in a healthy situation on Shooter's Hill, instead of in the Royal Arsenal, where the Royal Military Academy then stood: this permission, however, was not accompanied with any diminution of academical duty. Woolwich Common, in the vicinity of the Doctor's new residence, at that time exhibited little more than a few rude and scattered cottages, and was overgrown with thorns, briars, and furze-bushes. Speedily foreseeing what so elevated a situation, with extensive prospects and pure exhilarating air, might be rendered, he purchased land, employed brick-makers, directed the manufactory of his own bricks, planned and erected a series of genteel houses; and thus took the first and most important step towards rendering Woolwich Common what it now is, one of the most picturesque and salubrious places of residence in the vicinity of the British metropolis. On the removal of the Royal Military Academy from the Royal Arsenal to Woolwich Common in the year 1806, the Board of Ordnance purchased these houses of the Doctor, and converted them into official residences for Field-officers of Artillery, and the Professors of the Academy.

As a preceptor, Dr. Hutton was characterised by mildness, kindness, promptness in discovering the difficulties which his pupils experienced, patience in labouring to remove those difficulties, unwearied perseverance, and a neverfailing love of the act of communicating knowledge by oral instruction. His patience, indeed, was perfectly invincible. No dulness of apprehension, no forgetfulness in the pupil, ever induced him to yield to irascible emotions, or to forfeit his astonishing power of self-control. Those who have had favourable opportunities of acquainting themselves with the best modes of giving instruction, in the University of Cambridge, and in other institutions, both public and private, and who have been extensively engaged in the same profession, do not hesitate to say, that they never saw, or had the least conception of, any oral instructions, the excellences of which bore any comparison with those of Dr. Hutton.

As a lecturer, his manner was deliberate and perspicuous, his illustrations were happy and convincing, and his experiments were usually performed with neatness and success.

As an author, Dr. Hutton has long been the most popular of English mathematical writers; and there are obvious reasons for this popularity, which promises to be as permanent as it is extensive. His grand objects were utility in the topics of investigation, simplicity in the mode of their attainment or advancement. He had a constitutional, and a conscientious, aversion from the pedantry and parade of science. He loved science, and he promoted it for its own sake, and that of its tendencies. He never, by affecting to be abstruse, became obscure; nor did he ever slide into digressions, for the purpose of shewing how much he knew of other things besides those that were immediately under discussion. Hence, he was at once concise and perspicuous; and though he evidently wrote rather to be useful than to obtain celebrity, he procured for himself a reputation, such as hundreds, who have written for reputation alone, will never attain.

The valuable peculiarities of Dr. Hutton as a teacher, professor, and writer, emanated from intellectual and moral characteristics, which we cannot attempt to delineate fully. Suffice it to say, that he was remarkable for his unassuming deportment, for the simplicity of his habits, the mildness and equability of his temper, and the permanency and warmth of his personal attachments. He owed much to an undeviating regularity in the distribution of his time, to a correct and tenacious memory, (from which until he was more than 80 years of age scarcely any thing escaped,) and at the same time to as steady a practice of tabulating and classifying memoranda, on all subjects of conversation, speculation, and inquiry, as though he had no memory at all. The habits and dispositions of many men tend to stifle their genius, and preclude them from attaining eminence; but the habits and dispositions of Dr. Hutton all contributed to the maturity and perfection of his genius, by supplying that admirable stability of purpose, and continuity of effort, with which he always kept it under beneficial discipline.

During the last six or seven years, the Doctor's increasing infirmities led to rather more quiet and recluse habits than he had formerly adopted; though he became neither indolent nor estranged from his friends. Since the death of Mrs. Hutton, in 1817, his principal companion was his eldest daughter, Miss Hutton, whose exemplary devotedness to her valued parent, and affectionate anticipation of all his wishes and wants, he appreciated with commensurate affection. Though thus delighted with her society and attention, and those of his son, General Hutton, (who in 1821 removed to London, with his family, that they might assist in cheering his father's latter days,) he did not shut himself from his other friends, but always received them with a cordial welcome; and, nearly to the close of life, conversed with freedom and cheerfulness upon scientific and general topics. Latterly, if he had any previous intimation of the visit of a particular individual, he would, before the expected arrival, lay on his table a slip of paper, containing brief hints of the

main points interesting to both; that he might not, after his friend had retired, have the mortification of recollecting what he could have wished to remember earlier. His manuscript-journal, among other notices of a similar nature, contains, under the date of June 14th, 1820, a gratifying account (though too long to quote) of the pleasing reminis cences occasioned by a visit from Dr. Trail, (the well-known pupil and biographer of Dr. Robt. Simson,) an old friend, with whom he had formed an intimacy 50 years before, at Glasgow.

Much of Dr. Hutton's time was occupied in carrying through the press new editions of some or other of his works. Thus, during the last year of his life, he published the 15th edition of his "Arithmetic," the 8th edition of his "Compendious Measurer," and the 6th of his Mathematical Tables." In superintending the re-publication of this laborious and valuable work, however, he was materially assisted by his friend, Professor Leybourn, of the Royal Military College, Sandhurst.

In 1819 and 1820, the Doctor had some correspondence with that eminent philosopher Laplace, in reference to a point to which we have already adverted; viz. the extraordinary omission of the Doctor's name, when speaking of the determination of the mean density of the earth, Dr. Hutton's letter to Laplace remaining unanswered for several months, it was published in the Philosophical Magazine for February, 1820, as well as in the "Journal de Physique, &c." for April, 1820. In the "Connaissance des Tems," for 1823, published in November, 1820, Marquis Laplace did ample justice to our English philosopher, describing the nature and difficulty of the computation relative to the earth's density; and adding, "all this was executed in the most satisfactory manner by Dr. Hutton, an illustrious mathematician, to whom the abstruse sciences are indebted for numerous other important researches." Laplace also sent to the Doctor, in September, 1820, a letter, in which he apologized for his apparent neglect, stating that he had "long been acquainted