THE CONTEMPORARIES OF JAMES WATT. 133
many independent inventions, but also for the suggestions
and improvements which were often indispensable to the
formation and perfection of some of Watt's own inventions.
Murdoch was employed by Boulton & Watt in 1776,
and was made superintendent of construction in the engine.
department, and given general charge of the erection of en-
gines. He was sent into Cornwall, and spent in that district
much of the time during which he served the firm, crect-
ing pumping-engines, the construction of which for so
many years constituted a large part of the business of the
Soho establishment. He was looked upon by both Boulton
and Watt as a sincere friend, as well as a loyal adherent,
and from 1810 to 1830 was given a partner's share of the
income of the firm, and a salary of £1,000. He retired from
business at the last of the two dates named, and, dying in
1839, was buried near the two partners in Handsworth
Church.
Murdoch made a model, in 1784, of the locomotive pat- ented by Watt in that year. He devised the arrangement of "sun-and-planet wheels," adopted for a time in all of Watt's "rotative" engines, and invented the oscillating steam-engine (Fig. 36) in 1785, using the "D-slide valves," G, moved by the gear, E, which was driven by an eccentric. on the shaft, without regard to the oscillation of the cyl- inder, A. He was the inventor of a rotary engine and of many minor machines for special purposes, and of many machine-tools used at Soho in building engines and ma- chines. He seems, like Watt, to have had special fondness for the worm-gear, and introduced it wherever it could properly take the place of ordinary gearing. Some of the machines designed by Watt and Murdoch, who always worked well together, were found still in use and in good working condition by the author when visiting the works at Soho in 1873. The old mint in which, from 1797 to 1805, Boulton had coined 4,000 tons of copper, had then been pulled down, and a new mint had been erected in 1860.
