me money be wrought by this force of steam only, by esam into the open air after it has done its A: Mr. J. P. Muirhead saw this model drive I SEAL WISH rand the room in Mr. Murdoch's house at

IT:

Dr. William Small to Mr. Watt, dated The says: "Your very clever friend, Mr. 3 son, and is passed Friday evening with me, to my them I hoped soon to travel in a fiery The tribute afterwards borne by Vet these visitors was fully merited: "It was ve I learnt the other day the death of my vra Professor Robison. He was a man of the terest best and the most science of any body I have known, and sendship to me only ended with his life, after having

Le nearly half a century." Mr. Muirhead states that ummg the persons who saw this "working model" at Mr. Murach's was Mr. Richard Trevethick, who, in 1802, took La patent for an engine to be applied to the driving of Carriages, using the same principle with variations.

It is interesting to examine this model, in connexion with those complex, and in some instances, stupendous machines, of which the Exhibition supplied so many beautiful examples. Franklin said of the first balloon:-"It is a 'babe," but it Sy may become a giant." The balloon, however, is a "babe "still; the while the locomotive presents to it a most striking contrast; e if, in this model, we have "the babe," "the giant" is at hand sur cargo. inviting our contemplation. But it appears that the idea of a : Tw working rail never entered the mind of Watt; all that he seems to have Soho, the considered was, the movement of a carriage by steam on sms by cos-gas, ordinary roads. The m of Messrs.

1. Kies is repre

The second model exhibited by Messrs. J. Watt and Co. was that of an "oscillating engine," constructed at that early ," showing the period, for the purpose of illustrating Mr. Watt's patent of 1784, for making the cylinder work on its axis. For the representation of this model, see fig. 212.

anangement is peculiarly adapted to steam navigation, and of its use, the oscillating engines of Messrs. Penn, in the Exhibition, furnished highly-interesting examples.

in locomotive engines, may be judged from the representation, in fig. 214, of the leviathan "Lord of the Isles," exhibited in the Great Exhibition. This is a specimen of one of the ordinary class of engines constructed by the Great Western Company at their works at Swindon. The figure shows both the engine and the tender. It is capable of taking a passengertrain of 120 tons at an average speed of sixty miles an hour upon easy gradients. The evaporation of the boiler when in full work is equal to 1000-horse power; the effective power, as measured by a dynamometer, being equal to 743-horse power. The weight of the engine in working order is 35 tons, which does not include the tender, which, under similar circum stances, weighs 17 tons 13 cwts. The diameter of cylinder, 18 inches; the length of stroke, 24 inches; the diameter of the driving wheel, 8 feet; and the maximum pressure of steam, 120 lbs. The consumption of fuel with an average load of 90 tons, and an average speed of 29 miles an hour, including stoppages, as an ordinary mail train, averaged 20.8 lbs. of coke per mile. The stately proportions of this engine were seen to great advantage in the Crystal Palace; and, contrasted with the light locomotives of Messrs. Adams and England, seemed quite a giant of power and capability. To see this engine, however, in its full glory, the spectator should be at its side when it stops, after a heavy run at express speed; when its furnace is too white with heat for the naked eye to look upon without pain, and the steam, blowing off like thunder, shakes the very ground. One of these engines was nick-named by one of the men the "Emperor of Russia," on account of its extraordinary appetite for oil and tallow! In order to distribute the weight more equally over the rails, the engine alone has eight wheels. The cylinders were laid horizontally under the front end of the boiler, and could be very conveniently inspected, together with the rest of the Fig. 213.

From the exhibition of these two models, it appears very clearly that to the inventor of the steam-engine, James Watt, we are also indebted for the first ideas of locomotion by steam; and that the adjuncts of rails and paddles, and afterwards of screw-propellers, were added by other ingenious men who arose to put these ideas into practice. The idea obtained by Mr. Trevethick was carried into practice by himself and a Mr. Vivian, of Camborne near Redruth, in Cornwall, who jointly, in 1804, constructed and took out a patent for the first really useful locomotive. Fig. 213, is a representation of the side and end view of Messrs. Trevethick and Vivian's first locomotive. It consisted of a cylindrical boiler containing a tube of the U shape, one end of which formed the furnace, whilst to the other was connected the chimney. The power of the steam is conveyed to the wheels through the medium of the piston. This is made of metal, and slides in a cylinder, like the bucket of a pump in the barrel; and the steam being first let on to one side of it, forces it in one direction, and then on the other side, to force it in the other direction, thus keeps up the motion. The piston has a rod in the centre, passing through the cover at, one end of the cylinder, to the end of which is attached a connecting rod, which takes hold of a pin in one of the spokes of the wheel, and turns it just as a man's arm turns a coffee mill. The engraving shows this primitive arrangement; and the cylinder a is partially sunk into the boiler, and the power is transmitted through the rods bb to the wheels cc. An extraordinary misconception for a long period obstructed the use of locomotives. It was gravely alleged that the wheels would turn round without the engine advancing; and this

were

notion having once got abroad, people would hardly be per-
suaded to the contrary, even when they saw it with their own
yes. Much money and great ingenuity were expended in
making steam-walking machines, in which iron legs and feet
employed to push the engine along. George Stephenson,
1814, constructed a locomotive for the Killingworth Col-
ery, when all these crude ideas were swept away, and from
that time we may date the introduction of the locomotive
ystem. When the Liverpool and Manchester Railway was
projected in 1823, Mr. Stephenson and others spent large sums
money in improving the details of the engine; so that on
the opening of that railway a very excellent performance was
at once attained, and the benefits of the railway system began
to be appreciated. The great superiority of the engines used

working parts, by going down into the pit provided for that purpose under the engine.

This system, as may be imagined, is best suited for main lines, where the traffic is very heavy. It had, however, been foreseen by some of our engineers that the rage for the heavy engine would carry railway managers too far, and that when their eyes became open to the fact that more than half its power was exerted in moving itself merely, and knocking the rails and sleepers to pieces, they were as anxious to get back their light engines as they had formerly been to discard them. This led to the introduction of the light "locomotive carriage" of Mr. Adams, and the light engine of Mr. England. The specimens, which they exhibited, whilst possessing all the advantages which experience and skill have worked out in the on this line over that just described arose from the use of a heavy engines, are not more than one-third of the weight and which the flame passed, and which generated steam much more engine and carriage in one, so that there is no superfluous containing a number of tubes or small flues, through half the Costing. Adams' plan consists in combining the rapidly than the former boiler with a single large tube through it. weight. The boiler is a cylinder full of tubes placed verus Since that date, the increase of power that has taken place cally; but this plan, in subsequent engines, has been given up

of t

boiler

224

Pig. 214.

in favour of the ordinary horizontal construction, as shown in the locomotive carriage in the Exhibition.

Mr. England, on the other hand, combines the engine and tender in one frame, thus adapting it to carriages of the ordinary description. Both these plans have been satisfactorily tested in practice, and bear out the views of the projectors, the engines carrying a moderate load at a high speed, with a small consumption of fuel, and less injury to the permanent way. In addition to these, specimens from numerous other eminent engineers were exhibited. Mr. Trevethick, of the London and North-Western Company, sent the express engine, the "Cornwall," in which the boiler is placed very low, and the driving wheels are obtained of large size, by allowing the shaft on which they are fixed to pass through the boiler. Mr. Crampton, the patent narrow-gauge engine "Liverpool," said to be the most powerful engine in the world, being equal to 1140 horse power. The peculiarity of this engine consists in the position of the axle of the driving wheels, which is placed behind the fire-box. Mr. Fairbairn, of Manchester; Messrs. Wilson, of Leeds; and Messrs. Kitson, Thompson, and Hewitson, of the same town, exhi

bited specimens of the combined engine and tender variety, or "tank engines," as they are technically termed. There was also a very beautiful specimen of the first-class engine by Messrs. Hawthorn and Co., of Newcastle. The British visitor might consider, in dwelling on this collection of fire-steeds, that in this respect at least his country had no competitor. A traveller tells us, with pardonable exultation, how comforted and how much at home he felt at an Italian railway station, by seeing on the name-plate of the engine the familiar words, "Sharp, Roberts, and Co., Atlas Works, Manchester," and hearing a genuine English "All right!" given, before the train was allowed to move from the platform.

One of the greatest improvements in the application of the steam-engine, which was fully displayed in the Great Exhibition, is its employment in agriculture. Among others, Messrs. Ransome and May, of Ipswich, exhibited a portable steam-engine (fig. 215), adapted for thrashing and other agricultural purposes, which is of very simple construction, and, having but few working parts, there is little liability of its getting out of order; the cylinder and the machinery are placed on the top of the boiler, and are therefore constantly under the eye of the engine-man, and very easy of access. The engine is fitted up with a superior governor, and an effective

regulator-valve for stopping and controlling the speed of the engine. There is a simple and efficient feed-pump, which ensures at all times a regular supply of water to the boiler. The crank-shaft and connecting-rod are of wrought-iron, and the slide-valve

is of brass, and of the most approved construction. The steam and escape-pipes are of copper, and consequently not liable to injure the slide-valve and metallic packing of the piston, by any scales, caused by corrosion of the metal, coming off the pipes, and being carried by the steam into the working parts of the engine, as is frequently the case in common engines fi ted with wrought-iron gas-tubes (instead of copper) for steam-pipes. The boiler is of a superior description, and is made on the same principle as the best locomotive boilers, and will work with safety up to a pressure of 80 lbs. per square inch, if required.

This engine requires little fuel, and is free from danger by fire to the surrounding ricks and farm-buildings, the box being enclosed in a wrought-iron ash-pan, which contains water, and effectually extinguishes all hot cinders as they fall from the fire-grate. The engine is supported on a strong neat framing, which is carried on springs, interposed between it and the axles of the wheels. This arrangement effectually preserves the machinery from the injurious shocks caused by

and making the eccentric to contain the same area in its cross section as the piston, and by confining it in its extremes, or, in other words, by causing "an eccentric to revolve in its own diameter," is the same in principle as the arrangement employed in the ordinary engine.

It will be seen that A represents a steam chamber or "cylinder," and в the eccentric or "piston," which is keyed fast on the shaft c. The back plate, D, is fitted into the recess, and is pressed against the piston, either by means of springs, or by the admission of steam behind it by the small steam-pipe, and is introduced for the purpose of compensating for any wear that takes place in the periphery of the piston. It also performs another important office: in cases of priming, it is forced back, and the water rushes from one side to the other of the piston until it escapes. The plate E is dovetailed in and fitted fast, so that all wearing parts can be renewed with the greatest facility, compared with boring of cylinders, etc., in the ordinary engine. The piston is made steam-tight at both ends, with rings of metal, KK, fitted into conical seatings,

the roughness of the roads over which they frequently travel. These engines thrash, with ease, forty quarters of wheat of average yield per day, and are readily managed by an intelligent farm-servant, on whose care will depend, in a great measure, the quantity of fuel consumed.

which are cut open on one side, leaving a lap joint. The shaft c is carried on the vibrating rods FF, and vibrates the distance of the eccentricity of the piston-slots of suitable form being provided in the side plates, LL, to allow the shaft to traverso clear. GG are cranks, and нH are connecting-rods which Messrs. Simpson and Shipton's Patent Short-stroke Reci- convey the power from the piston to the lower cranks, through direct lines, and are always parallel. The steam is admitted procating Steam-Engine, shown in the Exhibition, though a those approximation to the ordinary engine in principle, differs into the cylinder precisely as in the ordinary engine, viz. teg materially in its mechanical construction. The peculiar pro-and bottom of the piston alternately; although the valve used perties of it are the direct conversion of rectilinear motion in this instance is rather different, as it exhausts through the imo circular, or the amalgamation of the piston and crank back, and is packed in a similar manner to the piston's enth motion in one body. Fig. 216, No. 1, is a side elevation, and being worked by an eccentric, weight, shaft, levers, etc., as in Fig. 216, No. 2, an end elevation of this engine. The eccentric, being a mechanical equivalent for a crank, if they be of the same "throw," and each attached to pistons of a certain area, they are equal in effect; by dispensing with the piston,

an ordinary arrangement.

The advantages claimed for this invention are as follows:

Teas of it receiving a reciprocating action from the steam, by reason of its mechanical arrangement, gives out a revolving y

loaded engines; but by the arrangements submitted, the crank shaft, which is the piston shaft, receives this shock, which is somewhat diminished on account of the piston itself gliding gradually out of equilibrium into full effect (the same as the common crank, though divested of the intermediate parts). An advantage is also obtained by working a short stroke with a large effective area of piston, and, consequently, a great speed, with slow velocity of the piston through space, is obtained, compared with the ordinary engine-thus the first motion can be