HISTORY OF ENGINEERING.
Rook I.
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piston-rod. To this axle was attached the first of the toothed wheels, and to the axle, onwhich were the driving wheels, was the other, similar in size to the first, and worked hv it.The steam cocks were open and shut by a connection with the crank axle. The force-pump, by which a supply of hot water contained in the casing which enclosed the cylin-drical fire-box, &c., was injected into the boiler, was also worked from it, as was a pair ofbellows.
Two years afterwards he obtained another patent, in which he specified the boiler ascylindrical, with flat ends, and an engine was built in conformity to it, which worked ona tram-road at Merthyr Tydvil , in South Wales. The wheels, though quite smooth,were found to have sufficient adhesion when the carriage drew ten tons of bar-iron, and itssupply of coals, at the rate of five miles an hour.
In the year 1811 Mr. Blenkinsop took out a patent for the first double-cylinderedengine. Here the boiler was circular, and the tube, which was connected with the fire,passed through the centre, and was bent up, to form the chimney. The cylinders, partlyin the boiler, were vertical, and 8 inches in diameter. The piston rods worked the con-necting rods by means of cross heads ; the two cranks were placed below the boiler, andmade to work two shafts fixed across the engine, on which were small-toothed wheels,working into a larger one between them.
On the axis of this, and outside the framing, were the driving wheels, one of which wastoothed and worked in a rack on one side of the railway : there were two pair of plain-flanged wheels, one before, and one behind, the driving pair. This engine weighed 5 tons,drew 94 tons on a level at 3£ miles per hour; its consumption of water per hour was50 gallons, and of coal 75 pounds.
In the following year another patent was taken out by the Messrs. Chapman, in whichmention is made for the first time of fanners to excite combustion, but we have no accountof the idea being carried into effect.
Numerous patents were taken out at various times by Mr. George Stephenson , Mr.I.oclce, and others none of which were practically applied until April, 1829, when thedirectors of the Liverpool and Manchester railway ottered a premium of 500/. for thebest locomotive engine. It was to draw on a level plane three times its own weight,at the rate of 10 miles pci hour, which weight was not to be more than 6 tons. The priceof the engine was restricted to 550/., the height of the chimney to l>e 15 feet, and the pressureon the boiler to be 50 pounds per square inch : it was to consume its own smoke; the wholeweight of boiler and engine was to be supported on springs and if the weight exceeded 4} 2tons, the engine was to have 6 wheels.
In October the trial was made by three competitors who owned the “ Rocket, ” the“Novelty,” and the “Sans Pared;” the ground chosen was on the Manchester side of Rain-hill Rridge, about 9 miles from Liverpool, where the road was level. The “ Rocket, ” theproduction of Mr. Robert Stephenson , the engineer of the London and Birmingham rail-way, was the only engine which performed the required distance of 70 miles with thegiven load and at the stipulated speed. It was constructed with four wheels not coupled ;the boiler was 6 feet long and 3 feet in diameter, and contained twenty-five copper tubes,3 inches in diameter, through which the heated air from the furnace passed to thechimney.
The furnace at the after end of the engine was 2 feet wide, and S feet high ; it had anexternal casing, between which and the fire-box was a space of 3 inches filled with water,and communicating with the boiler. The cylinders were placed on each side of the boiler,in an angular position, one end being nearly level with the top of the boiler at its after-end,and the other pointing towards the centre of the foremost or driving pair of wheels, withwhich the connection was made from the piston-rod to a pin on the outside of the wheel.The weight of the engine was 4 tons 5 cwt. The prize was of course awarded to Mr.Robert Stevenson, and from this time we may date the successful application of locomotivesto railroads.
Prior to this competition the greatest load drawn by locomotives was 43J tons, engineand tender included, 15 tons at 10 miles an hour, or 28J tons of goods including waggons,while the “ Rocket ” and tender, weighing only 7-£ tons, drew 44 tons gross, at the rate of 14per hour : this great result is principally to be attributed to the introduction of tubesin the boiler, by which the evaporating power was increased to three times that of theolder engines, with 40 per cent, less consumption of fuel, the invention of Mr. Seguin.Since the period above alluded to numerous patents have been taken out for improvingalmost every nortion of the locomotive engine.
Railways .— Iron railroads were not in use much before the commencement of the 17thcentury : previous to that time we find wooden rails employed at the coal works near New-castle, where one horse was enabled to draw 4 or 5 chaldrons in carts, with four rollers fittedto the rails, on which they ran with ease. These roads were about 6 feet in breadth :across them oak sleepers were laid from 4 to 8 inches square, at a distance of 2 or 3 feetapart; on their ends, the only parts perfectly squared, longitudinal timbers were peggeddown, 6 or 7 inches in bread'll, and 5 inches in depth, extending the whole length of the