Meanwhile Watt had vigilantly to defend his patents at home, which were assailed by unworthy and surreptitious rivals as soon as it was proved that they were pecuniarily valuable. Some of the competing engines, as Watt himself described them, were simply asthmatic. "Hornblower's, at Radstock, was obliged to stand still once every ten minutes to snore and snort." "Some were like Evan's mill, _which was a gentlemanly mill_; it would go when it had nothing to do, but it refused to work." The legal proceedings, both in equity and at common law, which now became necessary, were numerous. One bill of costs, from 1796 to 1800, amounted to between £5,000 and £6,000; and the mental and bodily labor, the anxiety and vexation, which were superadded, involved a fearful tax on the province of Watt's discoveries. With the year 1800 came the expiration of the privilege of the patent of 1769, as extended by the statute of 1775; and also the dissolution of the original copartnership of Messrs. Boulton and Watt, then of five-and-twenty years' duration. The contract was renewed by their sons, the business having become so profitable that Watt and his children were provided with a source of independent income; and at the age of sixty-four the great inventor had personally realized some of the benefits he contemplated. Henceforth Watt's ingenuity became excursive, discretionary, almost capricious; but in every phase and form it continued to be beneficent. In 1808 he founded a prize in Glasgow College, as an acknowledgment of "the many favors that learned body had conferred upon him." In 1816 he made a donation to the town of Greenock, "to form the beginning of a scientific library" for the instruction of its young men. Nor, amid such donations, were others wanting on his part, such as true religion prescribes, to console the poor and relieve the suffering. In 1816, on a visit to Greenock, Watt made a voyage in a steamboat to Rothsay and back again. In the course of this experimental trip he pointed out to the engineer of the boat the method of "backing" the engine. With a foot-rule he demonstrated to him what he meant. Not succeeding, however, he at last, under the impulse of the ruling passion (and we must remember he was then eighty), threw off his overcoat, and putting his hand to the engine himself, showed the practical application of his lecture. Previously to this, the "backstroke" of the steamboat engine was either unknown or not generally known. The practice was to stop the engine entirely a considerable time before the vessel reached the point of mooring, in order to allow for the gradual and natural diminution of her speed.