While the Carron foundry was pursuing a career of safe prosperity, Dr. Roebuck's enterprise led him to embark in coal-mining, with the object of securing an improved supply of fuel for the iron works. He became the lessee of the Duke of Hamilton's extensive coal-mines at Boroughstoness, as well as of the salt-pans which were connected with them. The mansion of Kinneil went with the lease, and there Dr. Roebuck and his family took up their abode. Kinneil House was formerly a country seat of the Dukes of Hamilton, and is to this day a stately old mansion, reminding one of a French chateau. Its situation is of remarkable beauty, its windows overlooking the broad expanse of the Firth of Forth, and commanding an extensive view of the country along its northern shores. The place has become in a measure classical, Kinneil House having been inhabited, since Dr. Roebuck's time, by Dugald Stewart, who there wrote his Philosophical Essays.[3] When Dr. Roebuck began to sink for coal at the new mines, he found it necessary to erect pumping-machinery of the most powerful kind that could be contrived, in order to keep the mines clear of water. For this purpose the Newcomen engine, in its then state, was found insufficient; and when Dr. Roebuck's friend, Professor Black, of Edinburgh, informed him of a young man of his acquaintance, a mathematical instrument maker at Glasgow, having invented a steam-engine calculated to work with increased power, speed, and economy, compared with Newcomen's; Dr. Roebuck was much interested, and shortly after entered into a correspondence with James Watt, the mathematical instrument maker aforesaid on the subject. The Doctor urged that Watt, who, up to that time, had confined himself to models, should come over to Kinneil House, and proceed to erect a working; engine in one of the outbuildings. The English workmen whom he had brought; to the Carron works would, he justly thought, give Watt a better chance of success with his engine than if made by the clumsy whitesmiths and blacksmiths of Glasgow, quite unaccustomed as they were to first-class work; and he proposed himself to cast the cylinders at Carron previous to Watt's intended visit to him at Kinneil.