French monarch; and in 1769 it was tried in the presence of the Duc de Choiseul, Minister of War, General Gribeauval, and other officers. At one of the experiments it ran with such force as to knock down a wall in its way. But the new vehicle, loaded with four persons, could not travel faster than two and a half miles an hour. The boiler was insufficient in size, and it could only work for about fifteen minutes; after which it was necessary to wait until the steam had again risen to a sufficient pressure. To remedy this defect, Cugnot constructed a new machine in 1770, the working of which was more satisfactory. It was composed of two parts—the fore part consisting of a small steam-engine, formed of a round copper boiler, with a furnace inside, provided with two small chimneys and two single-acting brass steam cylinders, whose pistons acted alternately upon the single driving-wheel. The hinder part consisted merely of a rude carriage on two wheels to carry the load, furnished with a seat in front for the conductor. This engine was tried in the streets of Paris; but when passing near where the Madeleine now stands, it overbalanced itself on turning a corner, and fell over with a crash; after which, its employment being thought dangerous, it was locked up in the arsenal to prevent further mischief. The machine is, however, still to be seen in the collection of the Conservatoire des Arts et Métiers at Paris. It has very much the look of a long brewer’s cart, with the addition of the circular boiler hung on at one end. Rough though it looks, it was a highly creditable piece of work, considering the period at which it was executed; and as the first actual machine constructed for the purpose of travelling on ordinary roads by the power of steam, it is certainly a most curious and interesting mechanical relic, well worthy of preservation.
But though Cugnot’s road locomotive remained locked up from public sight, the subject was not dead; for we find inventors employing themselves from time to time in attempting to solve the problem of steam locomotion in places far remote from Paris. The idea had taken root in the minds of inventors, and was striving to grow into a reality. Thus Oliver Evans, the American, invented a steam carriage in 1772 to travel on common roads; in 1787 he obtained from the State of Maryland an exclusive right to make and use steam-carriages, but his invention never came into use. Then, in 1784, William Symington, one of the early inventors of the steamboat, was similarly occupied in Scotland in endeavouring to develop the latent powers of the steam-carriage. He had a working model of one constructed, which he exhibited in 1786 to the professors of Edinburgh College; but the state of the Scotch roads was then so bad that he found it impracticable to proceed further with his scheme, which he shortly after abandoned in favour of steam navigation.
The same year in which Symington was occupied upon his steam-carriage, William Murdock, the friend and assistant of Watt, constructed his model of a locomotive at the opposite end of the island—at Redruth in Cornwall. His model was of small dimensions, standing little more than a foot high; and it was until recently in the possession of the son of the inventor, at whose house we saw it a few years ago. The annexed section will give an idea of the arrangements of this machine.
It acted on the high-pressure principle, and, like Cugnot’s engine, ran upon three wheels, the boiler being heated by a spirit-lamp. Small though the machine was, it went so fast on one occasion that it fairly outran its inventor. It seems that one night after returning from his duties at the Redruth mine, Murdock determined to try the working of his model locomotive. For this purpose he had recourse to the walk leading to the church, about a mile from the town. It was rather narrow, and was bounded on each side by high hedges. The night was dark, and Murdock set out alone to try his experiment. Having lit his lamp, the water boiled speedily, and off started the engine with the inventor after it. He soon heard distant shouts of terror. It was too dark to perceive objects; but he found, on following up the machine, that the cries proceeded from the worthy pastor of the parish, who, going towards the town, was met on this lonely road by the hissing and fiery little monster, which he subsequently declared he had taken to be the Evil One in propriá personâ. No further steps were, however, taken by Murdock to embody his idea of a locomotive carriage in a more practical form.
The idea was next taken up by Murdock’s pupil, Richard Trevithick, who resolved on building a steam-carriage adapted for common roads as well as railways. He took out a patent to secure the right of his invention in 1802. Andrew Vivian, his cousin, joined with him in the patent—Vivian finding the money, and Trevithick the brains. The steam-carriage built on this patent presented the appearance of an ordinary stage-coach on four wheels. The engine had one horizontal cylinder, which, together with the boiler and the furnace-box, was placed in the rear of the hind axle. The motion of the piston was transmitted to a separate crank-axle, from which, through the medium of spur-gear, the axle of the driving-wheel (which was mounted with a fly-wheel) derived its motion. The steam-cocks and the force-pump, as also the bellows used for the purpose of quickening combustion in the furnace, were worked off the same crank-axle.
John Petherick, of Camborne, has related that he remembers this first English steam-coach passing along the principal street of his native town. Considerable difficulty was experienced in keeping up the pressure of steam; but when there was pressure enough, Trevithick would call upon the people to “jump up,” so as to create a load upon the engine. It was soon covered with men attracted by the novelty, nor did their number seem to make any difference in the speed of the engine so long as there was steam enough; but it was constantly running short, and the horizontal bellows failed to keep it up.
This road-locomotive of Trevithick’s was one of the first high-pressure working engines constructed on the principle of moving a piston by the elasticity of steam against the pressure only of the atmosphere. Such an engine had been described by Leopold, though in his apparatus it was proposed that the pressure should act only on one side of the piston. In Trevithick’s engine the piston was not only raised, but was also depressed by the action of the steam, being in this respect an entirely original invention, and of great merit. The steam was admitted from the boiler under the piston moving in a cylinder, impelling it upward. When the motion had reached its limit, the communication between the piston and the under side was shut off, and the steam allowed to escape into the atmosphere. A passage being then opened between the boiler and the upper side of the piston, which was pressed downwards, the steam was again allowed to escape as before. Thus the power of the engine was equal to the difference between the pressure of the atmosphere and the elasticity of the steam in the boiler.
This steam-carriage excited considerable interest in the remote district near the Land’s End where it had been erected. Being so far removed from the great movements and enterprise of the commercial world, Trevithick and Vivian determined upon exhibiting their machine in the metropolis. They accordingly set out with it to Plymouth, whence it was conveyed by sea to London.
The carriage safely reached the metropolis, and excited much public interest. It also attracted the notice of scientific men, amongst others of Mr. Davies Gilbert, President of the Royal Society, and Sir Humphry Davy, both Cornishmen like Trevithick, who went to see the private performances of the engine, and were greatly pleased with it. Writing to a Cornish friend shortly after its arrival in town, Sir Humphry said: “I shall soon hope to hear that the roads of England are the haunts of Captain Trevithick’s dragons—a characteristic name.” The machine was afterwards publicly exhibited in an enclosed piece of ground near Euston Square, where the London and North-Western Station now stands, and it dragged behind it a wheel-carriage full of passengers. On the second day of the performance, crowds flocked to see it; but Trevithick, in one of his odd freaks, shut up the place, and shortly after removed the engine. It is, however, probable that the inventor came to the conclusion that the state of the roads at that time was such as to preclude its coming into general use for purposes of ordinary traffic.
While the steam-carriage was being exhibited, a gentleman was laying heavy wagers as to the weight which could be hauled by a single horse on the Wandsworth and Croydon iron tramway; and the number and weight of waggons drawn by the horse were something surprising. Trevithick very probably put the two things together—the steam-horse and the iron-way—and kept the performance in mind
