The Life of George Stephenson and of his Son Robert Stephenson / Comprising Also a History of the Invention and Introduction of the Railway Locomotive

by Samuel Smiles

The merit of Cugnot was, however, duly recognized. He was granted a pension of 300 livres, which continued to be paid to him until the outbreak of the Revolution. The Girondist Roland was appointed to examine the engine and report upon it to the Convention; but his report, which was favorable, was not adopted; on which the inventor's pension was stopped, and he was left for a time without the means of living. Some years later, Bonaparte, on his return from Italy after the peace of Campo Formio, interested himself in Cugnot's invention, and expressed a favorable opinion of his locomotive before the Academy; but his attention was shortly after diverted from the subject by the Expedition to Egypt. Napoleon, however, succeeded in restoring Cugnot's pension, and thus soothed his declining years. He died in Paris in 1804, at the age of seventy-five. Cugnot's locomotive is still to be seen in the Museum of the Conservatoire des Arts et Métiers at Paris; and it is, without exception, the most venerable and interesting of all the machines extant connected with the early history of locomotion.

While Cugnot was constructing his first machine at Paris, one Francis Moore, a linen-draper, was taking out a patent in London for moving wheel-carriages by steam. On the 14th of March, 1769, he gave notice of a patent for "a machine made of wood or metal, and worked by fire, water, or air, for the purpose of moving bodies on land or water," and on the 13th of July following he gave notice of another "for machines made of wood and metal, moved by power, for the carriage of persons and goods, and for accelerating boats, barges, and other vessels." But it does not appear that Moore did any thing beyond lodging the titles of his inventions, so that we are left in the dark as to what was their precise character.

James Watt's friend and correspondent, Dr. Small, of Birmingham, when he heard of Moore's intended project, wrote to the Glasgow inventor with the object of stimulating him to perfect his steam-engine, then in hand, and urging him to apply it, among other things, to purposes of locomotion. "I hope soon," said Small, "to travel in a fiery chariot of your invention." Watt replied to the effect that "if Linen-draper Moore does not use my engines to drive his carriages, he can't drive them by steam. If he does, I will stop them." But Watt was still a long way from perfecting his invention. The steam-engine capable of driving carriages was a problem that remained to be solved, and it was a problem to the solution of which Watt never fairly applied himself. It was enough for him to accomplish the great work of perfecting his condensed engine, and with that he rested content.

But Watt continued to be so strongly urged by those about him to apply steam-power to purposes of locomotion that, in his comprehensive patent of the 24th of August, 1784, he included an arrangement with that object. From his specification we learn that he proposed a cylindrical or globular boiler, protected outside by wood strongly hooped together, with a furnace inside entirely surrounded by the water to be heated except at the ends. Two cylinders working alternately were to be employed, and the pistons working within them were to be moved by the elastic force of the steam; "and after it has performed its office," he says, "I discharge it into the atmosphere by a proper regulating valve, or I discharge it into a condensing vessel made air-tight, and formed of thin plates and pipes of metal, having their outsides exposed to the wind;" the object of this latter arrangement being to economize the water, which would otherwise be lost. The power was to be communicated by a rotative motion (of the nature of the "sun and planet" arrangement) to the axle of one or more of the wheels of the carriage, or to another axis connected with the axle by means of toothed wheels; and in other cases he proposed, instead of the rotative machinery, to employ "toothed racks, or sectors of circles, worked with reciprocating motion by the engines, and acting upon ratched wheels fixed on the axles of the carriage." To drive a carriage containing two persons would, he estimated, require an engine with a cylinder 7 in. in diameter, making sixty strokes per minute of 1 ft. each, and so constructed as to act both on the ascent and descent of the piston; and, finally, the elastic force of the steam in the boiler must be such as to be occasionally equal to supporting a pillar of mercury 30 in. high.

Though Watt repeatedly expressed his intention of constructing a model locomotive after his specification, it does not appear that he ever carried it out. He was too much engrossed with other work; and, besides, he never entertained very sanguine views as to the practicability of road locomotion by steam. He continued, however, to discuss the subject with his partner Boulton, and from his letters we gather that his mind continued undetermined as to the best plan to be pursued. Only four days after the date of the above specification (i.e., on the 28th of August, 1784) we find him communicating his views on the subject to Boulton at great length, and explaining his ideas as to how the proposed object might best be accomplished. He first addressed himself to the point of whether 80 lbs. was a sufficient power to move a post-chaise on a tolerably good and level road at four miles an hour; secondly, whether 8 ft. of boiler surface exposed to the fire would be sufficient to evaporate a cube foot of water per hour without much waste of fuel; thirdly, whether it would require steam of more than eleven and a half times atmospheric density to cause the engine to exert a power equal to 6 lbs. on the inch. "I think," he observed, "the cylinder must either be made larger or make more than sixty strokes per minute. As to working gear, stopping and backing, with steering the carriage, I think these things perfectly manageable."

"My original ideas on the subject," he continued, "were prior to my invention of these improved engines, or before the crank, or any other of the rotative motions were thought of. My plan then was to have two inverted cylinders, with toothed racks instead of piston-rods, which were to be applied to two ratchet-wheels on the axle-tree, and to act alternately; and I am partly of opinion that this method might be applied with advantage yet, because it needs no fly and has some other conveniences. From what I have said, and from much more which a little reflection will suggest to you, you will see that without several circumstances turn out more favorable than has been stated, the machine will be clumsy and defective, and that it will cost much time to bring it to any tolerable degree of perfection, and that for me to interrupt the career of our business would be imprudent; I even grudge the time I have taken to make these comments on it. There is, however, another way in which much mechanism might be saved if it be in itself practicable, which is to apply to it one of the self-moving rotatives, which has no regulators, but turns like a mill-wheel by the constant influx and efflux of steam; but this would not abridge the size of the boiler, and I am not sure that such engines are practicable."

It will be observed from these explanations that Watt's views as to road locomotion were still crude and undefined; and, indeed, he never carried them farther. While he was thus discussing the subject with Boulton, William Murdock, one of the most skilled and ingenious workmen of the Soho firm—then living at Redruth, in Cornwall—was occupying himself during his leisure hours, which were but few, in constructing a model locomotive after a design of his own. He had doubtless heard of the proposal to apply steam to locomotion, and, being a clever inventor, he forthwith set himself to work out the problem. The plan he pursued was very simple and yet efficient. His model was of small dimensions, standing little more than a foot high, but 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 in. diameter and 2 in. stroke, was fixed in the top of the boiler, the piston-rod being connected with the vibrating beam attached to the connecting-rod which worked the crank of the driving-wheel. This little engine worked by the expansive force of the steam only, which was discharged into the atmosphere after it had done its work of alternately raising and depressing the piston in the cylinder.

SECTION OF MURDOCK'S MODEL.