260 WORKMEN AND HEROES ^ wheel-carriages for carrying persons and goods. To ascertain the exact number of strokes made by an engine during a given time, and thereby to check the cheats of the Cornish miners, Watt also invented the " Counter," with its several indexes. Among his leading improvements, introduced at various periods, were the throttle-valve, the application of the governor, the barometer or float, the steam-gauge, and the indicator. The term during which he seems to have thus combined the greatest maturity with the greatest activity of intellect, and the portion of his life which they comprehended, was from his fortieth to his fiftieth year. Yet it was a term of increased suffering from his acute sick-headaches, and remarkable for the infirmities over which he triumphed; notwithstanding, he himself complained of his "stupidity and want of the inventive faculty." Watt's chemical studies in 1 783, and the calculations they involved from ex* periments made by foreign chemists, induced him to make a proposal for a philo- sophical uniformity of weights and measures ; and he discussed this proposal with Priestley and Magellan. While Watt was examining the constituent parts of water, he had opportunities of familiar intercourse not only with Priestley, but with Withering, Keir, Edgeworth, Galton, Darwin, and his own partner, Boul- ton all men above the average for their common interest in scientific inquiries. Dr. Parr frequently attended their meetings, and they kept up a correspondence with Sir William Herschel, Sir Joseph Banks, Dr. Solander, and Afzelius. Mrs. Schimmelpenninck, who was greatly given to physiognomical studies, has left us this picture of Watt at this period.
- ' Mr. Boulton was a man to rule society with dignity ; Mr. Watt, to lead the
contemplative life of a deeply introverted and patiently observant philosopher. 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 intellectual development was magnificent ; compar- ison and causality immense, with large ideality and constructiveness, individual- ity, an enormous concentrativeness and caution. " He had a broad Scottish accent ; gentle, modest, and unassuming manners ; yet, when he entered a room, men of letters, men of science, nay, military men, artists, ladies, even little children, thronged round him. Ladies would appeal to him on the best means of devising grates, curing smoky chimneys, warming their houses, and obtaining fast colors. I can speak from experience of his teaching me how to make a dulcimer and improve a Jew's harp." In the year 1 786, Watt and Boulton visited Paris, on the invitation of the French Government, to superintend the erection of certain steam-engines, and especially to suggest improvements in the great hydraulic machine of Marly, which Watt himself designates a " venerable " work. In Paris Watt made many acquaintances, including Lavoisier, Laplace, Fourcfoy, and others scarcely less eminent ; and while here he discussed with Berthollet a new method of bleaching by chlorides, an invention of the latter which Watt subsequently introduced into England.
