CHAMBERS'S INFORMATION FOR THE PEOPLE. 



course, impossible in a locomotive to induce a . 

 draught through the furnace by means of a tall i 

 chimney, as is done in stationary and marine ! 

 engines. By the device of the blast-pipe, how- 

 ever, this difficulty is obviated, as the exhaust j 

 steam, rushing up the chimney, causes a sufficient 

 flow of air through the furnace. The cylinders, r, 

 are placed at the bottom of the smoke-box, and 

 partly inclosed in it In this engine, in order to 

 secure greater adhesion on the rails, the whole of 

 the six wheels are coupled together by connecting- 

 rods, as shewn at s, s. The engine is always 

 attended by a tender, in which the fuel and 

 water are conveyed. 



A few notes on the history of steam locomo- 

 tion may not be amiss in this place. The first 

 practical locomotive for working on a line of rails 

 (see INLAND CONVEYANCE) was that patented by 

 Richard Trevithick in 1804. It ran on a colliery 

 railway at Merthyr-Tydvil in Wales. Many of 

 the arrangements and appliances of the modern 

 locomotive are to be met with in this its earliest 

 form. One of the principal features of the loco- 

 motive of the present day the blast-pipe by 

 which the waste steam increases the draught 

 was used in this engine. 



It was, however, to the genius of the celebrated 

 George Stephenson that the modern locomotive 

 owed its existence. Others lent important aid in 

 perfecting the mechanical details ; but without 

 the admirable inventions of Stephenson in connec- 

 tion with railways, the locomotive could never 

 have arrived at its present efficiency. ' That the 

 modern locomotive,' says Mr Scott Russell, ' could 

 not subsist without the wrought-iron rail, and its 

 multifarious appendages of chains, keys, locks, 

 sleepers, switches, crossings, sidings, and turn- 

 tables, is too evident to need proof. Without the 

 smoothness of the rail, the engine would be jolted 

 to pieces ; and without the easy motion which it 

 gives, the engine could not be made to draw a 

 sufficiently profitable load to pay ; and further, 

 unless made of wrought-iron, it would be impos- 

 sible to attain the high speed of the locomotive 

 without imminent danger. It therefore appears 

 that the continuous wrought-iron railway and the 

 locomotive engine were inventions intimately 

 related to each other, and each a condition of 

 each other's success. To Stephenson we are 

 indebted for the chief features of both.' 



In 1814, being pecuniarily assisted by Lord 

 Ravensworth of Killingworth Colliery, he con- 

 structed a locomotive which was tried on a tram- 

 way there. This was subsequently improved, and 

 tried at other places ; but the mechanism of the 

 engines was not sufficiently well arranged to render 

 them economical and efficient, and in spite of his 

 exertions Stephenson failed to bring them into 

 use. The opening of the Manchester and Liverpool 

 Railway gave him an opportunity of bringing out 

 an efficient locomotive, worthy of the new field of 

 its operations. The result was the awarding of 

 the prize of ^500 for the best locomotive to the 

 Rocket, the engine entered by Stephenson. This 

 engine, which, with its own weight alone, traversed 

 the railway at a speed of twenty-nine miles an 

 hour, created an interest in the new power which 

 has never since then ceased to exist, and which, 

 by directing to it the attention of such able 

 mechanicians as Hackworth, Hawthorn, Fairbairn, 

 and many others, resulted in establishing that 



430 



wonder of modern times railway travelling. The 

 Rocket, after doing many years' work, is now placed 

 as an historical monument on a pedestal outside 

 Darlington Station. 



More or less akin to locomotive engines in their 

 general appearance and arrangement are port- 

 able and traction .engines. The former may be 

 described (with some self-contradiction) as loco- 

 motives that cannot propel themselves. They 

 consist of a locomotive boiler set on wheels, with 

 a small horizontal engine bolted on the top of it. 

 They are used mostly by farmers for working 

 agricultural machinery, and the wheels are to 

 enable them to be drawn by horses from place to 

 place about the farm. 



Traction engines are locomotives adapted to 

 run on common roads instead of on rails. The 

 greatest invention of recent date in connection 

 with them is Mr Thomson's ' Road-steamer,' the 

 essential feature of which is, that the wheels are 

 surrounded with thick rings of india-rubber, 

 forming their tires. This gives great adhesion 

 with a very light engine, and at the same time 

 greatly diminishes the jolting and vibration which 

 has hitherto been the destruction of almost all 

 traction engines. The principal drawback to these 

 engines at present seems to be the very high price 

 of the india-rubber tires ; and like all other in- 

 ventions, they require long trial and experiment 

 before they can be said to be quite perfect It 

 seems probable, however, that before many years we 

 shall see very much of the work now done by 

 horses executed by steam-power, just as machines 

 have to so large an extent superseded hand-labour 

 in factories. 



In the article MARITIME CONVEYANCE will be 

 found a full description of marine engines, so 

 that we need here only mention their leading 

 features. During the time when paddle-wheels 

 were the only means of propulsion used in steam- 

 vessels, there were two leading classes of marine 

 engines, the ' side-lever ' and the ' oscillating.' 

 The latter has been already described ; the former 

 was for a long time the form which was regarded 

 as the standard, and is illustrated in fig. 16. It is 



Fig. 16. 



a beam-engine, but in order to save height, the 

 beams (for there is one on each side) are placed 

 beside instead of above the cylinder. The piston- 

 rod cross-head is connected by links to one end 

 of the beams, and the connecting-rod is worked 

 by a cross-head from the other ends, the crank- 

 shaft being right over the connecting-rod end of 

 the beams. In all marine engines except the 

 very smallest two cylinders are used, working 

 cranks at right angles to each other, so as to 

 equalise the motion as far as possible, it being 

 impossible to use a fly-wheel for this purpose on 



