H thoroughly quantitative character? Weighing, measuring, calculating; such, indeed, was pre-eminently the essential nature of Cavendish's work. If, then, the claim of any one to be styled the founder of chemistry as a science rests upon his recognition of its quantitative relations, may we not also, and with equal truth, say that "Chemistry is an English Science-its founder was Cavendish, of immortal memory"? V JAMES WATT AND THE DISCOVERY OF THE COMPOSITION OF WATER BEING THE WATT ANNIVERSARY LECTURE DELIVERED BEFORE THE GREENOCK PHILOSOPHICAL SOCIETY ON 11TH MARCH 1898 WHEN your Secretary did me the honour to communicate the wish of the Committee that I should deliver this lecture, he was good enough to send me a list of the names of my predecessors in the position I was invited to occupy, together with a statement of the subjects on which they had addressed you. I confess I read his letter with very mingled feelings. To be asked to form one of such a distinguished company was in itself an honour which I deeply appreciated. On the other hand, it seemed well-nigh hopeless to find any theme associated with the life and work of the great man whose services to humanity we are this day called upon to commemorate that had not been dealt with by one or other of those who had preceded me. Naturally, and as befits the subject, the greater number of those who have spoken on these occasions have been distinguished engineers and mechanicians, and they have been able to speak with a fulness of knowledge and a weight of authority on the outcome of the great engineer's labours to which I, who know nothing of engineering or machinery, can have no pretensions. It has occurred to me, however, that there might be one incident in Watt's career which, in all probability, had not been handled by any one of those whom you have invited to appear here, and on which, as it comes within my own province, I thought I might venture, without presumption, to engage your attention. I was the more impelled to select it, in that it illustrates one side of Watt's intellectual activity which those who regard him only as an inventor and a mechanician are apt to undervalue, or even to lose sight of altogether. It serves, too, to throw additional light upon his mental character and his moral worth, and thus enables us to form a fuller and more just appreciation of the attributes of the man we wish to honour. The incident, in a word, relates to Watt's share in the establishment of the true view of the chemical nature of water. To the historian of science this is doubtless an old story on which it would be difficult to say anything new. The literature concerned with it occupies many volumes, largely owing to the circumstance that it has given rise to a controversy which has engaged the active interest of some of the strongest and subtlest intellects of this century. Some of the disputants have been men like Brougham, Jeffrey, and Muirhead, skilled in the arts of advocacy and in the faculty of eliciting and weighing evidence, who have stated their conclusions with all the "pomp and circumstance" of a judicial finding; others are men like Arago, Dumas, Harcourt, Whewell, Peacock, Kopp, George Wilson, eminent in science and literature, who have defended their convictions with great power, ample knowledge, much argumentative force, and occasional eloquence. At one time the contest was waged with no little fury and bitterness; it threatened, indeed, like the famous controversy as to the proper form of a lightning-conductor, during Sir John Pringle's presidency of the Royal Society, or like the equally famous controversy as to the true discoverer of the planet Neptune, to attain the dignity of a national question, far more acute, I should imagine, than that which has recently occasioned all right-feeling Scotchmen to approach the Queen in Council on the subject of Scotland's proper place and designation in Imperial concerns. But, happily, the acrimony and ill-feeling have long since passed away. There is no longer any need to discuss the question either as an advocate or as a partisan. What I shall attempt to-night is to treat it dispassionately, and, within the compass of an hour, to assess, as impartially as I am able, Watt's true place in regard to this discovery. It was indeed an epoch-making event. The discovery of the composition of water was as momentous for science as the greatest of Watt's inventions was for social and economic progress. The very fact itself, apart from all that flowed from it, was of transcendent interest. But to those who had eyes to see, its supreme importance was in its fruitful and far-reaching consequences. It signified nothing less than the passing away of an old order of things: the downfall of a system of philosophy which had outlived its usefulness, in that it no longer served adequately to interpret natural phenomena, and had become rather a hindrance and a stumbling-block to the perception of truth. The discovery at once led to the inception of a more rational and more truly comprehensive theory, which not only explained what was already known in a fuller, clearer, and more intelligible manner, but pointed the way to new facts hitherto undreamt of,-facts which in their turn served to strengthen and extend the generalisation which led to their discovery. No wonder, therefore, that those who loved and revered Watt, and who were rightly jealous of his honour, should have sought to do all in their power to vindicate what they honestly conceived to be his just title to so signal and so fundamental a discovery. No man has a juster claim to be regarded as a scientific man, in the truest and noblest sense of that term, than James Watt. The scientific spirit was manifest in him even in boyhood. The very circumstances of his condition, his weakly frame, the solitariness of his school - life, and the early habit of introspection thus induced in a mind forced to feed only on itself, served to strengthen and develop the instinct. Even his early struggles, and the jealousy of the Glasgow Guilds, which forbade him to practise his trade in the burgh in which he had not served an apprenticeship, conduced to mould his character and to determine the bent of his mind. Hard and illiberal as it seemed at the time, the Zunftgeist which drove him to the shelter of the old College in the High Street, and secured for him the abiding friendship of Black and Robison, was in reality the most fortunate circumstance of his career. It brought him directly under the influence of one of the greatest natural philosophers of his age, and stamped him permanently as a man of science. It would not be difficult to trace how this influence reacted upon all that Watt subsequently did-from the time of his earliest speculations on the loss of |