upon him the debt owing by Watt to Dr. Black amounting
to about 1200L., and undertook to find the requisite money to protect
the invention by means of a patent. The necessary steps were taken
accordingly and the patent right was secured by the beginning of 1769,
though the perfecting of his model cost Watt much further anxiety and
study.

It was necessary for Watt occasionally to reside with Dr. Roebuck at
Kinneil House while erecting his first engine there. It had been
originally intended to erect it in the neighbouring town of
Boroughstoness, but as there might be prying eyes there, and Watt
wished to do his work in privacy, determined "not to puff," he at
length fixed upon an outhouse still standing, close behind the mansion,
by the burnside in the glen, where there was abundance of water and
secure privacy. Watt's extreme diffidence was often the subject of
remark at Dr. Roebuck's fireside. To the Doctor his anxiety seemed
quite painful, and he was very much disposed to despond under
apparently trivial difficulties. Roebuck's hopeful nature was his
mainstay throughout. Watt himself was ready enough to admit this; for,
writing to his friend Dr. Small, he once said, "I have met with many
disappointments; and I must have sunk under the burthen of them if I
had not been supported by the friendship of Dr. Roebuck."

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