The Sans Pareil of Mr. Hackworth, (see the engraving on the opposite page,) does not materially differ from the Rocket, the most conspicuous variation being the vertical, instead of the inclined position, of the working cylinders. The boiler B is cylindrical, of the Trevithick kind, with one of its ends convex outwards, and the other flat. The fire-ban were of greater extent than usual, having an area of ten feet; and the flue-tube is returned to the front on one side of the fire place, where it enters the chimney C. This fire-tube is of course entirely surrounded by the water in the and hence a considerable surface (though not so great as in the Rocket and Novelty) of heated metal is brought into contact with the fluid to be evaporated. D represents one of the two working cylinders; these were seven inches in diameter, and had an eighteen-inch stroke. l he piston rods, through the medium of the vertical connecting rods, operated upon the hind pair of wheels; and the latter being connected to the fore wheels by the horizontal connecting rods, shown acting in the manner of cranks, motion was communicated to both pair of wheels,—an arrangement which is designed to cause a greater adhesion of the wheels to the rails, and of enabling the car riage to draw a greater load, than if only one pair of wheels was operated upon.
The Cyclopede, by Mr. Brandreth, which was also tried upon the railway, is represented in the cuts on pp.515, 516; Fig. 1 being a side elevation, and Fig. 2 a plan of the same. It consists in an endless chain a a a, made of planks, about an inch and a half thick, and four inches wide, extending across the bed of the carriage, attached at their extremities to ropes, and carried over a drum bb, at each end of the carriage, as shown in the plan at Fig. 2. To strengthen these cross pieces, and to prevent one of them from slipping down by itself, a cleat c c, is nailed on the end of each, and extends half-way across those next to it, on each side : the position of these, as they pass over the drums b b, will best show their extent and attachments. The chain platform is supported on a series of anti-friction rollers e e e e. The horse is yoked to the frame, and, by treading on the movable platform, drives it round, by which the drums b b are made to revolve, and, through the medium of the spur wheels, shown in the plan, puts in motion the carriage wheels. Two sets of spur-gear are provided, one at each end of the drum, so that either may be put in action at pleasure, and be adjusted according to the nature of the road, whether ascents, descents, or on horizontal planes, the speed or power being duly proportioned to the plane operated upon; r a represents the rope which is attached to tile endless chain, and w w the railway.
It will be observed, that by this arrangement the horse employed to propel the carriage is carried along with it, and thus a velocity of motion is produced in the machine far beyond the limits at which a horse can exert his power.
Now, as it has been ascertained that the resistance from friction on a level railway does not increase with an increase of speed, it follows, that in many cases much advantage might be obtained, by an increase of velocity greatly exceeding that at which a horse could exert his power, or even travel on the road, without exerting any power of traction. The principal objection raised against this plan is, that the horse has to carry his own weight ; but this objection equally applies to the locomotive steam-engine, in which the weight of one-horse power, including the water and fuel, falls very little, if at all, short of the weight of a draft horse. If we, however, suppose that the weight is increased thereby half a ton for the horse, it only amounts to a thirtieth part of his power of traction. An ordinary horse exerts throughout the day a force of 150 lbs. when moving at the rate of two miles an hour, and this is equivalent to 36,000 lbs. moved upon the Manchester and Liverpool railway. It has been shown upon several railways, that horses can, and do, move the load we have mentioned at their ordinary working pace. But it is to be presumed that such an arrangement of mechanism may be (though it has not yet been) pro duced, as will enable a horse, duly trained, to apply a portion of his weight as a mechanical force, in addition to his muscular exertion, which would render this mode of employing animal power highly effective and useful. There have been many attempts, prior to Mr. Brandreth's, to apply horse power on the same principle ; and it may be considered that they have hitherto all failed, from their not being continued in use : we are, nevertheless, of opinion, that the subject is still worthy of the attention of the mechanic.
To discover the cause of the great increase of speed, and the variable quan tities of fuel consumed by the different locomotive engines, which competed for the prize at the Manchester and Liverpool railway, Mr. Wood instituted the comparative view of each, which is exhibited in the following table, and to which we shall append his judicious comments.
" In examining the above, we find a very important effect in the economy of fuel, produced by:the Rocket over the old engines, in the proportion of 111 to 18.34, supposing the heating powers of coke and coal be equal. The cause of this is very obvious, and is entirely attributable to the use of the tubes of small diameter, presenting such an area of surface to the water in the boiler. These tubes were used at the suggestion of Mr. Booth, treasurer to the Liverpool and Manchester Railway Company, and nothing, since the introduction of those engines, has given such an impulse to their improvement.