In the first year of the present century, Watt withdrew himself entirely from business; but though he lived in retirement, he did not let his busy mind get rusty or sluggish for want of exercise. At one time he took it into his head that his faculties were declining, and though upwards of seventy years of age, he resolved to test his mental powers by taking up some new subject of study. It was no easy matter to find one quite new to him, so wide and comprehensive had been his range of study; but at length the Anglo-Saxon tongue occurred to him, and he immediately applied himself to master it, the facility with which he did so, dispelling all doubt as to the failing of his stupendous intellect. He thus busied himself in various useful and entertaining pursuits, till close upon his death, which took place in 1819.
Extraordinary as was Watt's inventive genius, his wide range of knowledge, theoretic and practical, was equally so. Great as is the "idea" with which his name is chiefly associated, he was not a man of one idea, but of a thousand. There was hardly a subject which came under his notice which he did not master; and, as was said of him, "it seemed as if every subject casually started by him had been that he had been occupied in studying." He had no doubt a rapid faculty of acquiring knowledge; but he owed the versatility and copiousness of his attainments above all to his unwearied industry. He was always at work on something or other, and he may truly be called one of those who—
"Could Time's hour-glass fall,
Would, as for seed of stars, stoop for the sand,
And by incessant labour gather all."
In a recent volume of memoirs by Mrs. Schimmel Pennick, we find the following graphic sketch of this extraordinary man:—"He was one of the most complete specimens of the melancholic temperament. His head was generally bent forward or leaning on his hand in meditation, his shoulders stooping, and his chest falling in, his limbs lank and unmuscular, and his complexion sallow. His utterance was slow and impassioned, deep and low in tone, with a broad Scotch accent; his manners gentle, modest, and unassuming. In a company where he was not known, unless spoken to, he might have tranquilly passed the whole time in pursuing his own meditations. When he entered the room, men of letters, men of science, many military men, artists, ladies, and even little children, thronged around him. I remember a celebrated Swedish artist being instructed by him that rat's whiskers made the most pliant painting-brushes; ladies would appeal to him on the best modes of devising grates, curing smoking chimneys, warming their houses, and obtaining fast colours."
His reading was singularly extensive and diversified. He perused almost every work that came in his way, and used to say that he never opened a book, no matter what its subject or worth, without learning something from it. He had a vivid imagination, was passionately fond of fiction, and was a very gifted story-teller himself. When a boy, staying with his aunt in Glasgow, he used every night to enthral the attention of the little circle with some exciting narrative, which they would not go to bed till they had heard the end of; and kept them in such a state of tremor and excitement, that his aunt used to threaten to send him away.
Since Watt's time, innumerable patents have been taken out for improvements in the steam engine; but his great invention forms the basis of nearly all of them, and the alterations refer rather to details than principles of action. The application of steam to locomotive purposes, however, led to the construction of the high pressure engine, in which the cumbrous condensing apparatus is dispensed with, and motion imparted to the piston by the elastic power of the steam being greater than that of the atmosphere.