Meanwhile, Cugnot, of Paris, had already made a road engine worked by steam power. It was first tried at the Arsenal in 1769; and, being set in motion, it ran against a stone wall in its way and threw it down. The engine was afterwards tried in the streets of Paris. In one of the experiments it fell over with a crash, and was thenceforward locked up in the Arsenal to prevent its doing further mischief. This first locomotive is now to be seen at the Conservatoire des Arts et Metiers at Paris.
Murdock had doubtless heard of Watt's original speculations, and proceeded, while at Redruth, during his leisure hours, to construct a model locomotive after a design of his own. This model was of small dimensions, standing little more than a foot and a half high, though it was sufficiently large to demonstrate the soundness of the principle on which it was constructed. It was supported on three wheels, and carried a small copper boiler, heated by a spirit lamp, with a flue passing obliquely through it. The cylinder, of 3/4 inch diameter and 2-inch stroke, was fixed in the top of the boiler, the piston-rod being connected with the vibratory beam attached to the connecting-rod which worked the crank of the driving-wheel. This little engine worked by the expansive force of steam only, which was discharged into the atmosphere after it had done its work of alternately raising and depressing the piston in the cylinder.
Mr. Murdock's son, while living at Handsworth, informed the present writer that this model was invented and constructed in 1781; but, after perusing the correspondence of Boulton and Watt, we infer that it was not ready for trial until 1784. The first experiment was made in Murdock's own house at Redruth, when the little engine successfully hauled a model waggon round the room,—the single wheel, placed in front of the engine and working in a swivel frame, enabling it to run round in a circle.
Another experiment was made out of doors, on which occasion, small though the engine was, it fairly outran the speed of its inventor. One night, after returning from his duties at the mine at Redruth, Murdock went with his model locomotive to the avenue leading to the church, about a mile from the town. The walk was narrow, straight, and level. Having lit the lamp, the water soon boiled, and off started the engine with the inventor after it. Shortly after he heard distant shouts of terror. It was too dark to perceive objects, but he found, on following up the machine, that the cries had proceeded from the worthy vicar, who, while going along the walk, had met the hissing and fiery little monster, which he declared he took to be the Evil One in propria persona!
When Watt was informed of Murdock's experiments, he feared that they might interfere with his regular duties, and advised their discontinuance. Should Murdock still resolve to continue them, Watt urged his partner Boulton, then in Cornwall, that, rather than lose Murdock's services, they should advance him 100L.; and, if he succeeded within a year in making an engine capable of drawing a post-chaise carrying two passengers and the driver, at the rate of four miles an hour, that a locomotive engine business should be established, with Murdock as a partner. The arrangement, however, never proceeded any further. Perhaps a different attraction withdrew Murdock from his locomotive experiments. He was then paying attention to a young lady, the daughter of Captain Painter; and in 1785 he married her, and brought her home to his house in Cross Street, Redruth.
In the following year,—September, 1786—Watt says, in a letter to Boulton, "I have still the same opinion concerning the steam carriage, but, to prevent more fruitless argument about it, I have one of some size under hand. In the meantime, I wish William could be brought to do as we do, to mind the business in hand, and let such as Symington and Sadler throw away their time and money in hunting shadows." In a subsequent letter Watt expressed his gratification at finding "that William applies to his business." From that time forward, Murdock as well as Watt, dropped all further speculation on the subject, and left it to others to work out the problem of the locomotive engine. Murdock's model remained but a curious toy, which he took pleasure in exhibiting to his intimate friends; and, though he long continued to speculate about road locomotion, and was persuaded of its practicability, he abstained from embodying his ideas of the necessary engine in any complete working form.
Murdock nevertheless continued inventing, for the man who is given to invent, and who possesses the gift of insight, cannot rest. He lived in the midst of inventors. Watt and Boulton were constantly suggesting new things, and Murdock became possessed by the same spirit. In 1791 he took out his first patent. It was for a method of preserving ships' bottoms from foulness by the use of a certain kind of chemical paint. Mr. Murdock's grandson informs us that it was recently re-patented and was the cause of a lawsuit, and that Hislop's patent for revivifying gas-lime would have been an infringement, if it had not expired.
Murdock is still better known by his invention of gas for lighting purposes. Several independent inquirers into the constituents of Newcastle coal had arrived at the conclusion that nearly one-third of the substance was driven off in vapour by the application of heat, and that the vapour so driven off was inflammable. But no suggestion had been made to apply this vapour for lighting purposes until Murdock took the matter in hand. Mr. M. S. Pearse has sent us the following interesting reminiscence: "Some time since, when in the West of Cornwall, I was anxious to find out whether any one remembered Murdock. I discovered one of the most respectable and intelligent men in Camborne, Mr. William Symons, who not only distinctly remembered Murdock, but had actually been present on one of the first occasions when gas was used. Murdock, he says, was very fond of children, and not unfrequently took them into his workshop to show them what he was doing. Hence it happened that on one occasion this gentleman, then a boy of seven or eight, was standing outside Murdock's door with some other boys, trying to catch sight of some special mystery inside, for Dr. Boaze, the chief doctor of the place, and Murdock had been busy all the afternoon. Murdock came out, and asked my informant to run down to a shop near by for a thimble. On returning with the thimble, the boy pretended to have lost it, and, whilst searching in every pocket, he managed to slip inside the door of the workshop, and then produced the thimble. He found Dr. Boaze and Murdock with a kettle filled with coal. The gas issuing from it had been burnt in a large metal case, such as was used for blasting purposes. Now, however, they had applied a much smaller tube, and at the end of it fastened the thimble, through the small perforations made in which they burned a continuous jet for some time."[7]
After numerous experiments, Murdock had his house in Cross Street fitted up in 1792 for being lit by gas. The coal was subjected to heat in an iron retort, and the gas was conveyed in pipes to the offices and the different rooms of the house, where it was burned at proper apertures or burners.[8] Portions of the gas were also confined in portable vessels of tinned iron, from which it was burned when required, thus forming a moveable gas-light. Murdock had a gas lantern in regular use, for the purpose of lighting himself home at night across the moors, from the mines where he was working, to his home at Redruth. This lantern was formed by filling a bladder with gas and fixing a jet to the mouthpiece at the bottom of a glass lantern, with the bladder hanging underneath.
Having satisfied himself as to the superior economy of coal gas, as compared with oils and tallow, for the purposes of artificial illumination, Murdock mentioned the subject to Mr. James Watt, jun., during a brief visit to Soho in 1794, and urged the propriety of taking out a patent. Watt was, however, indifferent to taking out any further patents, being still engaged in contesting with the Cornish mine-owners his father's rights to the user of the condensing steam-engine. Nothing definite was done at the time. Murdock returned to Cornwall and continued his experiments. At the end of the same year he exhibited to Mr. Phillips and others, at the Polgooth mine, his apparatus for extracting gases from coal and other substances, showed it in use, lit the gas which issued from the burner, and showed its "strong and beautiful light." He afterwards exhibited the same apparatus to Tregelles and others at the Neath Abbey Company's ironworks in Glamorganshire.