who then explained to me his doctrine of latent heat." 24 in 1764.

This was

Touching the steam-engine, Watt says:-"My attention was first directed in the year 1759 to the subject of steam-engines, by the late Dr. Robison himself, then a student in the University of Glasgow, and nearly of my own age. He at that time threw out an idea of applying the power of the steam engine to the moving of wheel carriages, and other purposes, but the scheme was not matured, and soon after abandoned on his going abroad.” 25

Watt's first improvement on the steam engine was made in 1765; and it consisted of the idea of introducing a separate condenser for the steam-a contrivance to prevent the cooling of the cylinder, and make the vacuum more perfect by condensing the steam in a vessel distinct from the cylinder. This was patented in the beginning of the year 1769, and in his specification he undertakes to lessen the consumption of steam and fuel in steam engines. This patent was renewed for a period of twenty-five years by an Act of Parliament in 1775. He took out another patent, in 1781, "for certain new methods of applying a continuous circular motion round an axis, and thereby give motion to the wheels of mills or other machines." The specification contains a description of five different modes of rotative motions. In 1782, he took out another patent, and the specification in this one contains six contrivances for equalising steam-power on the expansive principle; and among these, the double acting engine, in which the steam is alternately applied to press on each side of the piston, while a vacuum is formed on the other side.

One of the most important of his improvements of the steamengine was inserted in his patent of 1874. This is the "parallel motion," which he described thus :-"Methods of causing the pistonrods, pump-rods, and other parts of the engine, to move in perpendicular or other straight lines, and to enable the engine to act upon the working beams both in pushing and in pulling; and three varieties are described." This specification also described improved modes of applying the steam-engine to drive mills which have many wheels requiring to move round in concert; a simple method of applying the power of the steam-engine to the working of heavy

24 Letter and notes by Mr. Watt to Robison's Mechanical Philosophy, Vol. II., pp. 7, 8, 113-116,

25 Ibid., Vol. II., p. 113.

hammers or stampers; a portable steam-engine and machinery for moving wheeled carriages. 26

It was only after great perseverance, patience, hard toil, and thought, and many disappointments and untold anxieties that Mr. Watt at last attained success. It was fortunate for him, and for mankind, that from his first appearance in Glasgow he won not a few warm and able friends-men who knew and appreciated his great genius and the worth of his character, encouraged him, and stood by his side in one of the greatest trials of his life, to give their testimony to his rare genius and unimpeachable integrity.27

Watt entered into partnership with Mr. Boulton, of Birmingham, and, after 1775, for many years he resided in that city; and continued his exertions, with little intermission, to the further improvement of the steam engines. The business proved successful, and Watt retired at the end of the last century, leaving two of his sons in the establishment, which continued to prosper. The ingenious improver of the steam-engine, after many efforts and struggles, was enabled to spend the evening of his days in comparative wealth and leisure.

Mr. Watt invented many things beside his improvements of the steam-engine, amongst which may be mentioned a micrometer for measuring distances, which he used in his surveys of the Crinan and Gilp, and the Tarbert intended canals, and in other surveys of canals which he was employed to make; also, a copying-machine, which was patented in 1780, described as a "new method of copying

26 Watt's Notes to Robison's Mechanical Philosophy, Vol. II., pp. 118-121, 149-151; also Muirhead's Life of Watt, pp. 180, 247, 278-284, 285, 293-296.

27 With regard to two of the gentlemen alluded to above, I will quote Mr. Watt's own words :-"Although Dr. Black's theory of latent heat did not suggest my improvements on the steam-engine, yet the knowledge upon various subjects which he was pleased to communicate to me, and the correct modes of reasoning and of making experiments of which he set me the example, certainly conduced very much to facilitate the progress of my inventions; and I still remember with respect and gratitude the notice he was pleased to take of me when I very little merited it, and which continued throughout his life.

"To Dr. Robison I am also bound to acknowledge my obligations for very much information and occasional assistance in my pursuits, and above all for his friendship, which ended only with his life; a friendship which induced him, when I was beset with a host of foes, to come to London in the depth of winter, and appear as a witness for me in a court of justice, whilst labouring under an excessively painful disorder, which ultimately deprived him of life. To the remembrance of that friendship is principally owing my taking upon myself the office of his commentator at my advanced age."-Letter of Mr. Watt, in Robison's Mechanical Philosophy, Vol. II., p. 9.

letters and other writings expeditiously." At an early period of his career he built some organs. He planned and superintended the construction of the Monkland canal.

He wrote comparatively little, but he was an exceedingly wellinformed man. He was fond of chemistry as well as mechanics, and was well versed in the theory and practice of both. He discovered the composition of water, and his friends have maintained his priority to Cavendish in this discovery. He was elected a Fellow of the Royal Society of Edinburgh in 1748; of the Royal Society of London in 1785, and a correspondent member of the Institute of France in 1808. In 1806, the University of Glasgow conferred on him the honorary degree of LL.D.; and in 1814, the Academy of Sciences of the Institute of France elected him one of its eight foreign Associates. After the toils and heat of the day, his evening closed in calm serenity; full of honour and of years, beloved by his friends, and surrounded by his family, he passed away on the 25th of August, 1819, at Heathfield, near Birmingham, in the eighty-third year of his age. Statesmen, philosophers, men of science, and men of the world united in extolling the worth of his character and the greatness of his genius. From the notices of his death, I shall quote a part of the one which Lord Jeffrey wrote:

"We have said that Mr. Watt was the great improver of the steamengine; but, in truth, as to all that is admirable in its structure, or vast in its utility, he should rather be described as its inventor. It was by his inventions that its action was so regulated as to make it capable of being applied to the finest and most delicate manufactures, and its power so increased as to set weight and solidity at defiance. By his admirable contrivance, it has become a thing stupendous alike for its force and its flexibility-for the prodigious power which it can exert, and the ease, and precision, and ductility, with which it can be varied, distributed, and applied. It can engrave a seal, and crush masses of obdurate metal before it-draw out without breaking a thread as fine as gossamer, and lift a ship of war like a bauble in the air. It can embroider muslin and forge anchors, cut steel into ribbons, and impel loaded vessels against the fury of the winds and waves.

"It would be difficult to estimate the value of the benefits which these inventions have conferred upon this country. There is no branch of industry that has not been indebted to them; and, in all the most material, they have not only widened most magnificently

the field of its exertions, but multiplied a thousand-fold the amount of its productions. It has increased indefinitely the mass of human comforts and enjoyments, and rendered cheap and accessible, all over the world, the materials of wealth and prosperity. It has armed the feeble arm of man, in short, with a power to which no limits can be assigned; completed the dominion of mind over the most refractory qualities of matter; and laid a sure foundation for those future miracles of mechanic power which are to aid and reward the labours of after generations. It is to the genius of one man, too, that all this is mainly owing, and certainly no man ever bestowed such a gift on his kind. The blessing is not only universal, but unbounded; and the fabled inventors of the plough and the loom, who were deified by the erring gratitude of their rude contemporaries, conferred less important benefits on mankind than the inventor of our present steam-engine.

"This will be the fame of Watt with future generations; and it is sufficient for his race and his country. But to those to whom he more immediately belonged, who lived in his society and enjoyed his conversation, it is not, perhaps, the character in which he will be most frequently recalled, most deeply lamented, or even most highly admired. Independently of his great attainments in mechanics, Mr. Watt was an extraordinary, and in many respects a wonderful man. Perhaps no individual in his age possessed so much and such varied and exact information-had read so much, or remembered what he had read so accurately and well. He had infinite quickness of apprehension, a prodigious memory, and a certain rectifying and methodising power of understanding, which extracted something precious out of all that was present to it. His stores of miscellaneous knowledge was immense-and yet less astonishing than the command he had at all times over them. It seemed as if every subject that was casually started in conversation with him, had been that which he had been last occupied in studying and exhausting; such was the copiousness, the precision, aud the admirable clearness of the information which he poured out upon it without effort or hesitation. Nor was this promptitude and compass of knowledge confined in any degree to the studies connected with his ordinary pursuits. That he should have been minutely and extensively skilled in chemistry and the arts, and in most of the branches of physical science, might perhaps have been conjectured; but it could not have been inferred from his usual occupations, and probably is not generally known

that he was curiously learned in many branches of antiquity, metaphysics, medicine, and etymology, and perfectly at home in all the details of architecture, music, and law. He was well acquainted, too, with most of the modern languages, and familiar with their most recent literature. Nor was it at all extraordinary to hear the great mechanician and engineer detailing and expounding, for hours together the metaphysical theories of the German logicians, or criticising the measures or the matter of the German poetry.

"It is needless to say, that, with those vast resources, his conversation was at all times rich and instructive in no ordinary degree: but it was, if possible, still more pleasing than wise, and had all the charms of familiarity, with all the substantial treasures of knowledge. No man could be more social in his spirit, less assuming or fastidious in his manners, or more kind and indulgent towards all who approached him. He had a certain quiet and grave humour, which ran through most of his conversation, and in a vein of temperate jocularity, which gave infinite jest and effect to the condensed and inexhaustible information which formed its main staple and

characteristic.

"In his temper and disposition he was not only kind and affectionate, but generous, and considerate of the feelings of all around him; and gave the most liberal assistance and encouragement to all young persons who showed any indications of talent, or applied to him for patronage or advice. All men of learning and science were his cordial friends; and such was the influence of his mild character and perfect fairness and liberality, even upon the pretenders to these accomplishments, that he lived to disarm even envy itself, and died, we verily believe, without a single enemy."

The application of steam power to navigation in the end of the last century, and to railway trains in the present, has produced the most striking results; and although Watt was not directly connected himself with the early attempts of steam navigation, still its introduction was greatly dependent on his improvements of the steamengine. The development of steam-power in manufactories and other forms will be afterwards noticed; but before quitting the subject, I will describe the earliest attempts to propel ships by steam. Many projects were spoken of which were never realised. But Mr. Miller of Dalswinton, assisted by Mr. James Taylor, tutor in his family, formed a plan for vessels with paddle wheels to be driven by a steam-engine; and with the assistance of Mr. Symington of Wan