economy of steam was obtained; together with the power of varying the effort of the engine according to the work which it has to do, by admitting the steam through a greater or smaller portion of the stroke. These are the chief improvements which Watt effected at different periods of his life. Of the patient ingenuity by which they were rendered complete, and the many beautiful contrivances by which he gave to senseless matter an almost instinctive power of self-adjustment, with precision of action more than belongs to any animated being, we cannot speak; nor would it be easy to render description intelligible without the help of diagrams. His first patent bears date June 5, 1769, so that some time elapsed between the invention and publication of his improvements. The delay arose partly from his own want of funds, and the difficulty of finding a person possessed of capital, who could appreciate the merit of his invention; partly from his own increasing occupation as a civil engineer. In that capacity he soon acquired reputation, and was employed in various works of importance. In 1767 he made a survey for a canal, projected, but not executed, between the Clyde and Forth. He also made the original survey for the Crinan Canal, since carried into effect by Mr. Rennie; and was employed extensively in forming harbours, deepening rivers, constructing bridges, and all the most important labours of his profession. The last and greatest work of this kind on which he was employed, was a survey for a canal between Fort William and Inverness, where the Caledonian Canal now runs. At last Dr. Roebuck, the establisher of the Carron iron-works, became Watt’s partner in the patent, upon condition that he should supply the necessary funds for bringing out the invention, and receive in return two-thirds of the profit. That gentleman, however, was unable to fulfil his share of the contract, and in 1774 resigned his interest to Mr. Boulton, the proprietor of the Soho works, near Birmingham. Watt then determined to remove his residence to England; a step to which he probably was rendered more favourable by the death of his wife in 1773. In 1775, Parliament, in consideration of the national importance of Mr. Watt’s inventions, and the difficulty and expense of introducing them to public notice, prolonged the duration of his patent for twenty-five years.