"The cocks of the cold water may be moved by the great work, but the steam cocks must be managed by the hand of the charioteer, who also directs the rudder-wheel. [Then follow his rough diagrams.] The central wheel ought to have been under the rollers, so as it may be out of the way of the boiler.”* After farther explaining himself, he goes on to say: "If you could learn the expense of coals to a common fire-engine and the weight of water it draws, some certain estimate may be made if such a scheme as this would answer. Pray don't show Wyat this scheme, for if you think it feasible and will send me a critique upon it, I will certainly, if I can get somebody to bear half the expense with me, endeavor to build a fiery chariot, and, if it answers, get a patent. If you choose to be partner with me in the profit, and expense, and trouble, let me know, as I am determined to execute it if you approve of it. "Please to remember the pulses of the common fire-engines, and say in what manner the piston is so made as to keep out the air in its motion. By what way is the jet d'eau froid let out of the cylinder? How full of water is the boiler? How is it supplied, and what is the quantity of its waste of water ?" It will be observed from these remarks that the doctor's notions were of the crudest sort, and, as he obviously contemplated but a modification of the Newcomen engine, then chiefly employed in pumping water from mines, the action of which was slow, clumsy, and expensive, the steam being condensed by injection of cold water, it is clear that, even though Boulton had taken up and prosecuted Darwin's idea, it could not have issued in a practicable or economical working locomotive. But, although Darwin himself—his time engrossed by his increasing medical practice-proceeded no farther with his scheme of a “fiery chariot," he succeeded in inflaming the mind of his young friend, Richard Lovell Edgeworth, who had settled for a time in his neighborhood, and induced him to direct his attention. to the introduction of improved means of locomotion by steam. In a letter written by Dr. Small to Watt in 1768, we find him describing Edgeworth as "a gentleman of fortune, young, mechanical, and indefatigable, who has taken a resolution to move land and water carriages by steam, and has made considerable * Soho MSS. + Ibid. CHAP. I.] MR. EDGEWORTH'S SCHEMES. 57 progress in the short space of time that he has devoted to the study." One of the first-fruits of Edgeworth's investigations was his paper "On Railroads," which he read before the Society of Arts in 1768, and for which he was awarded the society's gold medal. He there proposed that four iron railroads be laid down on one of the great roads out of London; two for carts and wagons, and two for light carriages and stage-coaches. The post-chaises and gentlemen's carriages might, he thought, be made to go at eight 'miles an hour, and the stage-coaches at six miles an hour, drawn by a single horse. He urged that such a method of transport would be attended with great economy of power and consequent cheapness. Many years later, in 1802, he published his views on the same subject in a more matured form. By that time Watt's steam-engine had come into general use, and he suggested that small stationary engines should be fixed along his proposed railroad, and made, by means of circulating chains, to draw the carriages along with a great diminution of horse labor and expense. It is creditable to Mr. Edgeworth's forethought that both the models proposed by him have since been adopted. Horse-traction of carriages on railways is now in general use in the towns of the United States; and omnibuses on the same principle regularly ply between the Place de la Concorde at Paris and St. Cloud, both being found highly convenient for the public, and profitable to the proprietors. The system of working railways by fixed engines was also regularly employed on some lines in the infancy of the railway system, though it has since fallen into disuse, in consequence of the increased power given to the modern locomotive, which enables it to surmount gradients formerly considered impracticable. Besides his speculations on railways worked by horse and steam power, Mr. Edgeworth-unconscious of the early experiments of Stevins and Mackworth-made many attempts to apply the power of the wind with the same object. It is stated in his "Memoirs" that he devoted himself to locomotive traction by various methods for a period of about forty years, during which he made above a hundred working models, in a great variety of forms; and though none of his schemes were attended with practical success, he adds that he gained far more in amusement than he lost by his unsuccessful labors. "The only mortification that affected me," he says, " was my discovery, many years after I had taken out my patent [for the sailing-carriage], that the rudiments of my whole scheme were mentioned in an obscure memoir of the French Academy." The sailing-wagon scheme, as revived by Mr. Edgeworth, was doubtless of a highly ingenious character, though it was not practicable. One of his expedients was a portable railway, of a kind somewhat similar to that since revived by Mr. Boydell. Many experiments were tried with the new wagons on Hare Hatch Common, but they were attended with so much danger when the wind blew strong—the vehicles seeming to fly rather than roll along the ground-that farther experiments were abandoned, and Mr. Edgeworth himself at length came to the conclusion that a power so uncertain as that of the wind could never be relied upon for the safe conduct of ordinary traffic. His thoughts finally settled on steam as the only practicable power for this purpose; but, though his enthusiasm in the cause of improved transit of persons and of goods remained unabated, he was now too far advanced in life to prosecute his investigations in that direction. When an old man of seventy he wrote to James Watt (7th August, 1813): "I have always thought that steam would become the universal lord, and that we should in time scorn posthorses. An iron railroad would be a cheaper thing than a road on the common construction. Four years later he died, and left the problem, which he had nearly all his life been trying ineffectually to solve, to be worked out by younger men. Dr. Darwin had long before preceded him into the silent land. Down to his death in 1802, Edgeworth had kept up a continuous correspondence with him on his favorite topic; but it does not appear that Darwin ever revived his project of the "fiery chariot." He was satisfied to prophesy its eventual success in the lines which are perhaps more generally known than any he has written for, though Horace Walpole declared that he could read the Botanic Garden over and over again forever," the poetry of Darwin is now all but forgotten. The following was his prophecy, published in 1791, before any practical locomotive or steam-boat had been invented: CHAP. I.] DR. DARWIN'S PROPHECY. "Soon shall thy arm, unconquered steam, afar And armies shrink beneath the shadowy cloud." 59 The prophecy embodied in the first two lines of the passage has certainly been fulfilled, but the triumph of the steam balloon has yet to come. CHAPTER II. EARLY LOCOMOTIVE MODELS. THE application of steam-power to the driving of wheel-carriages on common roads was in 1759 brought under the notice of James Watt by his young friend John Robison, then a student at the University of Glasgow. Robison prepared a rough sketch of his suggested steam-carriage, in which he proposed to place the cylinder with its open end downward, to avoid the necessity for using a working beam. Watt was then only twenty-three years old, and was very much occupied in conducting his business of a mathematical instrument maker, which he had only recently established. Nevertheless, he proceeded to construct a model locomotive provided with two cylinders of tin-plate, intending that the pistons and their connecting-rods should act alternately on two pinions attached to the axles of the carriagewheels. But the model, when made, did not answer Watt's expectations; and when, shortly after, Robison left college to go to sea, he laid the project aside, and did not resume it for many years. In the mean time, an ingenious French mechanic had taken up the subject, and proceeded to make a self-moving road engine worked by steam-power. It has been incidentally stated that a M. Pouillet was the first to make a locomotive machine,* but no particulars are given of the invention, which is more usually attributed to Nicholas Joseph Cugnot, a native of Void, in Lorraine, where he was born in 1729. Not much is known of Cugnot's early history beyond that he was an officer in the army, that he published several works on military science, and that on leaving the army he devoted himself to the invention of a steam-carriage to be run on common roads. It appears from documents collected by M. Morin that Cugnot *"Portfeuille du Conservatoire des Arts et Métiers," Livraison 1, p. 3. |