among these isles, charmed with the kind and luxurious hospitality of the insular chieftains, and interested by the simplicity and peculiarity of Highland manners. At last they returned within the bourne of lowland life. Johnson, having talked down the Edinburgh-men, departed for London; and Boswell betook himself for the winter to the ungrateful business of the Scottish bar. The world expected a book or two to be the results of the Hebudean travels of Boswell and Johnson; nor were they disappointed. Within a reasonable length of time after Johnson's return to London, appeared his account of his 'Journey to the Western Isles of Scotland.' Boswell's little bark, although not quite so soon launched as the great first-rate of his friend, was, however, to sail attendant on its triumph. His Tour to the Hebrides' did not appear in print till a number of years after. It was then received by the public with an avidity which even exceeded that with which Johnson's book had been bought and read. It is filled chiefly with the detail of Johnson's conversation and minutest acts during the journey It added also lights, shades, drapery, and colouring, to that great portrait of the Scottish Highlands, which Johnson had drawn with a pencil careless of all but the primary and essential proportions and the grandest effects it showed Boswell to have acquired new acuteness of discernment, and new stores of knowledge, since he wrote his Account of Corsica; but it at the same time proved him to have busied himself about trifles, till trifling was almost all the business of which he was capable; it evinced the truth of Johnson's observation of him, "that he wanted bottom !"

From the era of this famed Hebudean excursion till the time of his father's death, Boswell's life ran on in its usual tenor, undistinguished by any remarkable change in its circumstances or habits. He continued to make frequent visits to London,-to linger as long as possible upon every visit, amidst the fascinating society to which his presence was there acceptable,—and to leave it upon every occasion of his return to Scotland with the reluctance and depression of one driven into exile from a scene of pure unmingled joy. His predilection for London determined him at length entirely to relinquish the Scottish bar for the English bar, and he entered himself as a student at the Temple. Lord Auchinleck soon after died, and James, as his eldest son, succeeded to the possession of the family estates. The rents exceeded not fifteen hundred pounds a year; a jointure to his mother-in-law was to be paid out of this income; and James himself was but a life-renter, enjoying the produce but bound up by a strict entail from impairing the capital. For a little he found the change in his condition not unpleasant; but his revenue was soon experienced to be inadequate to his wishes. Mrs Boswell's health began to decline; the affairs of his estate for a time detained him from revisiting London; his wonted fits of low spirits occasionally returned; and his ordinary happiness quickly settled rather under than above the same mediate level as before. He had hopes that Mr Pitt, with the generous gratitude of a youthful heart, would reward his services with a place or pension; but Mr Pitt found it easier to put him off with a simple complimentary letter. Upon a subsequent occasion he ventured to offer himself a candidate for the representation of the county of Ayr; but other interests quickly threw him at a distance in the competition

He at length fixed his residence in London, and offered himself as a candidate for business at the English bar. His beginnings were here also not unpromising. By the favour of Lord Lonsdale he obtained the respectable appointment of Recorder of Carlisle. He attended the judges in pursuit of business upon several of their circuits; and was sometimes retained to plead in a Scottish appeal. But his habits of conviviality, his character for flighty gaiety incompatible with eminence in business, the lateness of the time in life at which he made the attempt, and perhaps also his want of perseverance, soon stopped him short in his career of juridical practice in England as before in Scotland. His first ardour was gradually extinguished; he relinquished the hope of becoming more eminent in Westminster-hall than he had been in the parliament-house at Edinburgh; he even resigned the office of Recorder of Carlisle, and resolved henceforth to court only the praise of literature and colloquial sprightliness.

It was extremely fortunate for the lovers of literary anecdote, and of the memory of Johnson, that he was driven to adopt this resolution. Having treasured up with wonderful diligence the better part of what had fallen from his late friend Johnson, in many of the conversations in which he had excited or listened to Johnson's wisdom and colloquial eloquence, from the commencement of their acquaintance to the period of his friend's death, he now undertook to compose a biographical account of that great man, in which those treasured gleanings from his colloquial dictates should be carefully interwoven. This book was, with much care and pains, composed, conducted through the press, and presented to the public. By the public it was at first sight received with some measure of prejudice against it; for who could suppose that he who could not make up a moderate octavo, without introducing into it a number of trifles unworthy to be written or read, should have furnished out two copious quartos of the biography of a single man of letters, otherwise than by filling them with trifles. But every reader was soon pleasingly disappointed. It was found to exhibit an inimitably. faithful picture of the mingled genius and weakness, the virtues and vices, the sound sense and pedantry, the benignity and passionate harshness, of the great though not consummately perfect man, the train of whose life it endeavoured to unfold. Johnson was seen in it, not as a solitary figure, but associated with those groups of his distinguished contemporaries with which it was his good fortune, in all the latter and more illustrious years of his life, often to meet and converse. It displayed many fine specimens of the manner in which, in the latter part of the eighteenth century, literature and philosophical wisdom were liable to be carelessly intermingled in the ordinary conversation of the best company in Britain. It preserved a thousand precious anecdotical memorials of the state of arts, manners, and policy among us during this period, such as must be invaluable to the philosophers and antiquarians of a future age.

The publication of this work was the last eminently-conspicuous event in Boswell's life. He died on the 19th of June, 1799.1

Abridged from a memoir in the Monthly Magazine' for 1803.

Joseph Black.

BORN A. D. 1728.-DIED A. D. 1799.

THE foundation of philosophical chemistry was laid in Britain by Dr Cullen. Until about the year 1730, chemistry, in this country at least, was little else than the art of preparing medicines; and the only business of its public professors was to impart to medical students some little knowledge of the principal chemical agents and their action, with an exclusive view to the methods of preparing the different articles of the pharmacopoeia. Dr Cullen's chemical prelections in the college of Glasgow first conferred something like the dignity of a science upon chemistry; and it was his lectures that first incited and directed Black to that course of research which ended in the establishment of the great doctrine of latent heat, and those discoveries respecting lime and magnesia which conducted other chemists to the true theory of gases.

Joseph Black was born of British parents at Bourdeaux in France, in the year 1728. He spent in Bourdeaux and its vicinity the first twelve years of his life, at the end of which period he was sent to Belfast, where he received the rudiments of his literary education, which he completed in the university of Glasgow. In the course of his studies, he does not appear to have entered very deeply into the abstract sciences; his predilection for chemistry was early and decided, and he passed his time chiefly in the investigations of experimental philosophy. In making choice of a profession he selected that of medicine, as being the most nearly related to his favourite studies.

No

He graduated at Edinburgh in 1754. His inaugural dissertation printed on this occasion contains an outline of one of his great discoveries, the nature of the alkaline earths and the properties of fixed air. It was entitled 'De Humore acido a cibris orto et Magnesia alba.' In 1756 he communicated his ideas on this subject at greater length in a paper which he read before a philosophical society in Edinburgh.' thing could exceed in simplicity the methods which our chemist pursued in conducting his researches even at this early period of his investigations. "In the same year," he says, "in which my first account of these experiments was published, namely 1757, I had discovered that this particular kind of air, attracted by alkaline substances, is deadly.to all animals that breathe it by the mouth and nostrils together; but that if the nostrils were kept shut, I was led to think that it might be breathed with safety. I found, for example, that when sparrows died in it in ten or eleven seconds, they would live in it for three or four minutes when the nostrils were shut by melted suet. And I convinced myself, that the change produced on wholesome air by breathing it, consisted chiefly, if not solely, in the conversion of part of it into fixed air. For I found that by blowing through a pipe into lime-water, or a solution of caustic alkali, the lime was precipitated, and the alkali was rendered mild. I was partly led to these experiments by some observations of Dr Hales,

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in which he says that breathing through diaphragms of cloth dipped in alkaline solution, made the air last longer for the purposes of life. In the same year, I found that fixed air is the chief part of the elastic matter which is formed in liquids in the vinous fermentation. Van Helmont had indeed said this, and it was to this that he first gave the name gas silvestre. It could not long be unknown to those occupied in brewing or making wines. But it was at random that he said it was the same with that of the grotto del Cane in Italy-but he supposed the identity, because both are deadly-for he had examined neither of them chemically, nor did he know that it was the air disengaged in the effervescence of alkaline substances with acids. I convinced myself of the fact, by going to a brew-house with two phials, one filled with distilled water, and the other with lime-water. I emptied the first into a vat of wort fermenting briskly, holding the mouth of the phial close to the surface of the wort. I then poured some of the lime-water into it, shut it with my finger, and shook it. The lime-water became turbid immediately. Van Helmont says that the dunste, or deadly vapour burning charcoal, is the same gas silvestre; but this was also a random conjecture. He does not even say that it extinguishes flame; yet this was known to the chemists of his day. I had now the certain means of deciding the question, since, if the same, it must be fixed air. I made several indistinct experiments as soon as the conjecture occurred to my thoughts; but they were with little contrivance or accuracy. In the evening of the same day that I discovered that it was fixed air that escaped from fermenting liquors, I made an experiment which satisfied me. Unfixing the nozzle of a pair of chamber bellows, I put a bit of charcoal, just red hot, into the wide end of it, and then quickly putting it into its place again, I plunged the pipe to the bottom of a phial, and forced the air very slowly through the charcoal, so as to maintain its combustion, but not produce a heat too suddenly for the phial to bear. When I judged that the air of the phial was completely vitiated, I poured lime-water into it, and had the pleasure of seeing it become milky in a moment." The course of investigation thus opened up for the first time was afterwards pursued by Cavendish and Priestley, and undoubtedly conducted them to those brilliant discoveries which have rendered their names immortal in the annals of chemical science.

In the same year, 1756, Dr Black was appointed to the chair of chemistry and anatomy in Glasgow, vacant by the resignation of his preceptor, Cullen. From this period his attention was necessarily much occupied by the routine of teaching. Before the year 1763, however, he bad brought his next grand set of experiments and inquiries on the absorption of heat to a conclusion. He removed from Glasgow to Edin. burgh in 1766, where he again succeeded Cullen as professor of chem istry. From this period, says his biographer Mr Robison, he." formed the firm resolution of directing his whole study to the improvement of his scholars in the elementary knowledge of chemistry. He saw too many of them with a very scanty stock of previous learning; he had many from the workshop of the manufacturer, who had none at all; and he saw that the number of such hearers must increase with the increasing activity and prosperity of the country: and these appeared to

him as by no means the least important part of his auditory. To engage the attention of such pupils, and to be perfectly understood by the most illiterate, was therefore considered by Dr Black as his most sacred duty. Plain doctrines, therefore, taught in the plainest manner, must employ his chief study. That no help may be wanting, all must be illustrated by suitable experiments, by the exhibition of specimens, and the management of chemical processes. Nice and abstruse philosophical opinions would not interest such hearers; any doctrines, inculcated in a refined manner, and referring to elaborate disquisitions of others, would not be understood by the major part of an audience of young persons, as yet only beginning their studies. To this resolution Dr Black strictly adhered, endeavouring every year to make his courses more plain and familiar, and illustrating them by a great variety of examples in the way of experiment. No man could perform these more neatly and successfully. They were always ingeniously and judiciously contrived, clearly establishing the point in view, and never more than sufficed for this purpose. While he scorned the quackery of a showman, the simplicity, neatness, and elegance, with which they were performed, were truly admirable. Indeed the simplex munditiis stamped every thing that he did. I think it was the unperceived operation of this impression that made Dr Black's lectures such a treat to all his scholars. They were not only instructed, but (they knew not how) delighted; and without any effort to please, but solely by the natural emanation of a gentle and elegant mind, co-operating, indeed, with a most perspicuous exhibition of his sentiments, Dr Black became a favourite lecturer; and many were induced, by the report of his students, to attend his courses, without having any particular relish for chemical knowledge, but merely in order to be pleased. This, however, contributed greatly to the extending the knowledge of chemistry; and it became a fashionable part of the accomplishment of a gentleman."

Dr Black's only publications, subsequent to his Edinburgh appointment, were a paper on the effects of boiling upon water in disposing it to freeze more readily, printed in the London Philosophical Transactions' for 1774, and an analysis of the water of some hot springs in Iceland, in the Edinburgh Philosophical Transactions' for 1791. He

died in 1799.

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Mr Robison has given us an interesting sketch of the personal habits and general demeanour of this illustrious philosopher. "I have already observed," says he, "that when I was first acquainted with Dr Black, his aspect was comely and interesting. As he advanced in years his countenance continued to preserve that pleasing expression of inward satisfaction, which, by giving ease to the beholder, never fails to please. His manner was perfectly easy, and unaffected, and graceful. He was of most easy approach, affable, and readily entered into conversation, whether serious or trivial. His mind being abundantly furnished with matter, his conversation was at all times pertinent and agreeable; for Dr Black's acquirements were not merely those of a man of science. He was a stranger to none of the elegant accomplishments of life. He therefore easily fell into any topic of conversation, and supported his part in it respectably. He had a fine, or accurate musical ear, and a voice which would obey it in the most perfect manner; for he sung,