Professor G-ORDON <m Locomotive Carriages. 25 



locomotive on the Great Western, namefl the " Iron Duke,'' weighing 36 

 tons, and the tender 14 tons, making 50 tons, with water for a run of 

 about 50 miles. Professor Gordon then briefly sketched the history of 

 the present railway system, which may be considered as having originated 

 with the Stockton and Darlington Company in 1825, when the locomotive 

 engine was yet in its infancy. The system was further developed in 

 1829 by the formation of the Liverpool and Manchester railway. The 

 Professor called especial attention to the circumstance, that up till 1830, 

 the success of the system was held to depend chiefly on goods traffic. But 

 it soon became apparent that the traffic in goods, for which the Liverpool 

 railway was principally constructed, was subordinate to the passenger 

 traffic, the development of which Mr. Stephenson, Mr. Locke, and other 

 eminent engineers, soon discovered to be — what is now universally admitted 

 — the real source of the prosperity of the railway system. Mr. Gordon 

 proceeded to discuss the questions of the present average weight of 

 locomotive engines and tender — the amount of adhesion — the power and 

 efficiency of the engine. Mr. Stephenson's engine, the "Rocket," con- 

 structed in 1829, according to the condition on which the Directors of 

 the Liverpool and Manchester railway ofi'ered a premium, weighed 4 tons 5 

 cwt.; its tender, with water and coke, 3 tons 4 ewt, : and its power was 

 equal to drawing two carriages, weighing, with load, 9J tons, at the rate 

 of 15 miles per hour. The locomotive was afterwards gradually increased 

 in weight to 6, 8, 10, and, in 1834, to 12 tons; and it has subsequently 

 been increased to a weight varying from 18 to 25 tons on narrow gauge 

 lines, and 24 to 35 on broad gauge lines, including water and coke ; while 

 the tender has been increased, on narrow gauge lines to 29 tons, and on 

 broad gauge lines to 42 tons. This increase of weight, it was shown, 

 was rendered necessary by the demand for an increase of power, which 

 could not be obtained without a corresponding increase of adhesion. The 

 adhesion, bemg the friction between the surface of the rail and the peri- 

 phery of the driving-wheel, bears a certain proportion to the insistent 

 weight on the driving-wheels, varying with the state of smoothness of the 

 rail and wheels, according to Mr. Stephenson, and from one-sixth to one- 

 thirteenth of the insistent weight, the amount of adhesion to be relied on 

 depending on the weight of the train and the gradients on the line. As 

 to the efficiency of the engine, it was shown, that all engines, as engines, 

 might be made equally efficient. The question was not here as to their 

 absolute efficiency, but as to the part of the efi"ective power of the loco- 

 motive engine absorbed by tlie work done, i.e. the transport of a certain 

 weight of passengers. It appeared from the data examined by the Pro- 

 fessor, that for the ordinary passenger traffic on first class railways, from 

 65 to 60 per cent, of all the effective power expended is required to move 

 the locomotive itself; and in railways of small traffic, the modern locomo- 

 tive absorbs from GO to 75 per cent, of the power developed in the 

 cylinders, or at the periphery of the driving-wheels. 



