250 EIGHTH REPORT 1838. 



To a certain extent the force of this objection may be admitted. 

 The fastest trains, however, on the Liverpool and Manchester 

 railway, viz. the 11 o'clock first-class train consists invariably of 

 four coaches and no more. The trains of passengers, however, 

 generally consist of from seven to nine coaches, and it is in- 

 tended before the next meeting of the Association to extend the 

 experiments to trains of this magnitude. It will then be seen 

 whether the lightness of the train increases the proportionate 

 resistance at a given speed, and if so, to what extent. 



A summary of the results of the experiments contained in 

 this Report is exhibited in the annexed table. It is, however, 

 to be regretted that the effects of the wind were such as to 

 render these results not so exact as could be wished. Still 

 they may be regarded as tolerable approximations, all circum- 

 stances considered. The experiments which appear to be en- 

 titled to most attention and likely to give the most accurate re- 

 sults, were those made with the train of four first-class coaches 

 on the Whiston plane. 



In reviewing the results of these experiments, the near agree- 

 ment of the several values obtained for the friction proper from 

 different experiments by different principles and processes of 

 calculation, is sufficiently striking, and affords a presumption 

 of truth. Before, however, conclusions apparently so much in 

 discordance with all previous estimates of resistance on railways 

 can be accepted with confidence, it will be necessary to multiply 

 and vary the experiments, and more especially to do so with a 

 view to meet the objections which have been brought against 

 some of those detailed in the present Report. Meanwhile, 

 whatever be the source of the resistance to the tractive power, 

 and whatever may be its exact amount, it does appear to be 

 established by tolerably conclusive evidence that the resistance 

 of railway trains at high speeds is considerably greater than the 

 common estimate : and, on the other hand, that at low speeds 

 it is probably less. Should it appear upon further investigation 

 that the motive power necessary on railways has a material de- 

 pendence on the speed, and that at high speeds, such as velo- 

 cities from thirty to forty miles an hour, its amount is as con- 

 siderable as the experiments here detailed would indicate, some 

 important changes must be admitted in the principles which have 

 hitherto guided those who have projected and constructed rail- 

 ways. 



If it be admitted that the power engaged in opposing friction 

 forms but a small part of the whole power used in working rail- 

 ways at high speeds, it will become a matter of comparatively 

 small importance to contrive means of diminishing an obstruc- 



