interest, and ambition, pursuing a difficult and thankless task with unchanging ardour, the friend of princes, yet unsullied even by the suspicion of a bribe, devoting his whole income, beyond a scanty maintenance, to the service of the cause which his life was spent in advocating.

The Rajah continued to cherish Schwartz's memory. He commissioned Flaxman for a monument erected to him at Tanjore; he placed his picture among those of his own ancestors; he erected more than one costly establishment for charitable purposes in honour of his name; and, though not professing Christianity, he secured to the Christians in his service not only liberty, but full convenience for the performance of their religious duties. Nor were the Directors backward in testifying their gratitude for his services. They sent out a monument by Bacon to be erected in St. Mary's Church at Madras, with orders to pay every becoming honour to his memory, and especially to permit to the natives, by whom he was so revered, free access to view this memorial of his virtues.

It is to be regretted that no full memoir of the life and labours of this admirable man has been published. It is understood that his correspondence, preserved by the Society for promoting Christian Knowledge, would furnish ample materials for such a work. The facts of this account are taken from the only two memoirs of Schwartz which we know to be in print,— a short one for cheap circulation published by the Religious Tract Society; and a more finished tribute to his memory in Mr. Carne's Lives of Eminent Missionaries,' recently published. We conclude in the words of one whose praise carries with it authority, Bishop Heber: "Of Schwartz, and his fifty years' labour among the heathen, the extraordinary influence and popularity which he acquired, both with

Mussulmans, Hindoos, and contending European governments, I need give you no account, except that my idea of him has been raised since I came into the south of India. I used to suspect that, with many admirable qualities, there was too great a mixture of intrigue in his character—that he was too much of a political prophet, and that the veneration which the heathen paid, and still pay him (and which indeed almost regards him as a superior being, putting crowns, and burning lights before his statue), was purchased by some unwarrantable compromise with their prejudices. I find I was quite mistaken. He was really one of the most active and fearless, as he was one of the most successful missionaries, who have appeared since the Apostles. To say that he was disinterested in regard of money, is nothing; he was perfectly careless of power, and renown never seemed to affect him, even so far as to induce an outward show of humility. His temper was perfectly simple, open, and cheerful; and in his political negotiations (employments which he never sought, but which fell in his way) he never pretended to impartiality, but acted as the avowed, though certainly the successful and judicious agent of the orphan prince committed to his care, and from attempting whose conversion to Christianity he seems to have abstained from a feeling of honour*. His other converts were between six and seven thousand, besides those which his companions and predecessors in the cause had brought over."

He probably acted on the same principle as in conducting the English schools above mentioned, using "no deceitful methods." That he was earnest in recommending the means of conversion, appears from a dying conversation with his pupil, Serfogee Rajah.

JOSEPH BLACK was born in 1728, near Bordeaux, in France, where his father, a native of Ireland, but of Scottish extraction, who was engaged in the wine trade, then resided. In 1740 young Black was sent home to receive the rudiments of education at a grammar-school in Belfast. Thence he went, in 1746, to Glasgow, and having chosen the profession of medicine, proceeded in that university with the preliminary studies.

At that period, Dr. Cullen had just entered on the then untrodden paths of philosophical chemistry in his lectures, at which Black was an assiduous attendant. He soon formed an intimacy with his instructor, with whom he associated himself in the toils of the laboratory. It was here that he laid the foundation of his future attainments and discoveries, in an accu

rate and practical knowledge of the science as far as it then reached, and above all in the cultivation of habits of precise and cautious inductive investigation.

In 1750 he removed to Edinburgh to complete his medical course; and it was in connexion with the important inquiries belonging to that department that he made his first discoveries in chemistry.

His first object of research was one which possessed high medical as well as chemical interest-the nature and properties of magnesia. This substance had hitherto been confounded with lime: Dr. Black first showed it to be characterised by peculiar properties which demonstrate its distinct nature as a separate species of earth. The second point of his investigation was the difference between mild and caustic alkalies, between limestone and quick-lime, common and calcined magnesia, &c. The whole of this subject was at that period involved in complete obscurity. Dr. Black showed, by simple and decisive experiments, the real condition of these substances, and indicated the general law by which they are governed, viz.—that the difference consists merely in the combination of the simple earth or alkali with a peculiar air, which is driven off by heat, and which was called fixed air by him, and carbonic acid gas by later chemists. He did not, however, prosecute the inquiry into the nature and properties of this gas. This discovery supplied the foundation on which all subsequent researches and theories have been built. He gave an account of these investigations in an inaugural dissertation, composed as an exercise on taking his Doctor's degree, and in a paper entitled Experiments on Magnesia Alba, &c.,' first published in the Edinburgh Physical and Literary Essays' in 1755.

It was almost immediately after the publication of these researches that Dr. Cullen was elected Pro

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F

fessor of Chemistry at Edinburgh. The reputation which Dr. Black had now acquired pointed him out as the proper person to succeed to the vacant chair at Glasgow, to which he was accordingly appointed in 1756. His department included chemistry and medicine; and he also practised as a physician. His lectures soon became highly popular from the clearness of his style and method, and the beauty and simplicity of his experimental illustrations. He did not, however, prosecute his inquiries, in that particular department of chemistry in which he had already had so much success. But in another branch of science his power of original research was signally displayed.

The relation of bodies to heat, especially in connexion with the changes of state they undergo, was a subject which had hitherto excited hardly any notice; and though some effects were such as might have been supposed obvious, still no one had as yet reasoned on them, or understood their nature.

It is a characteristic of great genius to find important matter of reflection in objects which the vulgar pass by as too common to excite notice, and Dr. Black having remarked some very common facts with regard to heat, was conducted to those great discoveries on which his celebrity rests-that of latent heat, and that of specific heat; which last term is, in fact, only another mode of expressing the same principle. This great truth, the foundation of all our determinate ideas of the causes of those diversities of physical condition which the same mass of matter is capable of assuming, seems to have suggested itself to the mind of the discoverer about the year 1757.

After the invention of the thermometer, it had been among the earliest facts observed that changes in the state of bodies, such as boiling, freezing, melting, &c., take place always at certain fixed temperatures as indicated by the thermometer; and at a different degree of the scale, for each different substance.