When Watt explained to Smeaton, the architect of Eddystone Lighthouse and the greatest engineer of the day, the plan of his steam engine, he doubted whether mechanics could be found capable of executing the different parts with sufficient precision; and, in fact, in 1769, when Watt produced, under the patronage of Dr. Roebuck, his third model, with a cylinder of block tin eighteen inches in diameter, there were only one or two men capable of giving the requisite truth of workmanship to air-pump cylinders of two inches in diameter. At the present day, as before observed in reference to Wolverton, there are thousands of skilled workmen employed at weekly wages, to whom the most difficult problems of Watt's early experiments are familiar handiwork. At Handsworth, too, working for a long life in the Soho manufactories as the servant, confidential assistant, and friend, lived another remarkable man, William Murdoch, the inventor of illumination by gas, and the author of the first locomotive steam engine, and of several important contributions to practical science, to which justice has scarcely been done. William Murdoch employed coal gas so early as 1792, for the purpose of lighting his house and offices at Redruth, in Cornwall, when he was superintending the pumping engines erected there by Messrs. Boulton and Watt; for it was he who erected for them in that district the first Cornish pumping engine, with separate condenser. He had at that time in regular use a portable gas lantern, formed by filling a bladder with gas, and fixing to it a jet, which was attached to the bottom of a glass lantern, which he used for the purpose of lighting himself home at night across the moors from the mining engines. His locomotive engine, made upon the non-condensing principle (since adopted in all engines for that purpose), was constructed, in consequence of a lameness which confined him to the sofa, and set to work at Redruth in 1784. It is still in existence in perfect working order, and was exhibited before a meeting of the Mechanical Engineers at Birmingham, in the year 1850, when a memoir of Mr. Murdoch was read, which has been kindly forwarded to us by the President, John M'Connell, Esq., C.E. It is among the traditions of Redruth, that one night William Murdoch, wishing to try an experiment with his new invention, lighted the lamp under the boiler, and set it a-going on a narrow, smooth, hard-rolled gravel walk leading to the church, a mile distant. The little engine went off at a great pace, whistling and hissing as it went, and the inventor followed as fast as he could in chase. Soon he heard cries of alarm, horror, despair, and came up to the worthy clergyman of the parish cowering up against the hedge, almost in a fainting fit, under a strong impression that it was the Evil One in person who just hissed past him in a fire-flaught.