But more serious troubles were rapidly accumulating upon Dr. Roebuck himself; and it was he, and not Watt, that sank under the burthen. The progress of Watt's engine was but slow, and long before it could be applied to the pumping of Roebuck's mines, the difficulties of the undertaking on which he had entered overwhelmed him. The opening out of the principal coal involved a very heavy outlay, extending over many years, during which he sank not only his own but his wife's fortune, and--what distressed him most of all--large sums borrowed from his relatives and friends, which he was unable to repay. The consequence was, that he was eventually under the necessity of withdrawing his capital from the refining works at Birmingham, and the vitriol works at Prestonpans. At the same time, he transferred to Mr. Boulton of Soho his entire interest in Watt's steam-engine, the value of which, by the way, was thought so small that it was not even included among the assets; Roebuck's creditors not estimating it as worth one farthing. Watt sincerely deplored his partner's misfortunes, but could not help him. "He has been a most sincere and generous friend," said Watt, "and is a truly worthy man." And again, "My heart bleeds for him, but I can do nothing to help him: I have stuck by him till I have much hurt myself; I can do so no longer; my family calls for my care to provide for them." The later years of Dr. Roebuck's life were spent in comparative obscurity; and he died in 1794, in his 76th year. He lived to witness the success of the steam-engine, the opening up of the Boroughstoness coal,[4] and the rapid extension of the Scotch iron trade, though he shared in the prosperity of neither of those branches of industry. He had been working ahead of his age, and he suffered for it. He fell in the breach at the critical moment, and more fortunate men marched over his body into the fortress which his enterprise and valour had mainly contributed to win. Before his great undertaking of the Carron Works, Scotland was entirely dependent upon other countries for its supply of iron. In 1760, the first year of its operations, the whole produce was 1500 tons. In course of time other iron works were erected, at Clyde Cleugh, Muirkirk, and Devon--the managers and overseers of which, as well as the workmen, had mostly received their training and experience at Carron--until at length the iron trade of Scotland has assumed such a magnitude that its manufacturers are enabled to export to England and other countries upwards of 500,000 tons a-year. How different this state of things from the time when raids were made across the Border for the purpose of obtaining a store of iron plunder to be carried back into Scotland!