315 



siderable as to preclude the application of tractive power by 

 ropes, at velocities exceeding twenty miles per hour. 



I have not attempted to estimate numerically each of such 

 losses, but will refer to an example. 



When the rope was employed between the Euston-square 

 and the Camden-town stations of the London and Birming- 

 ham Railway, it was estimated by Mr. R,. Stephenson, that 

 only one-half of the power of the engine was usefully applied 

 to the train. 



All the methods of using ropes appear inevitably liable to 

 considerable loss by the inaction of the stationary engines 

 between the running of trains. 



The various causes of loss of power in working locomotive, 

 compared with stationary, steam engines, are — 



That the greatest possible quantity of steam must be 

 generated in the least possible space or dimensions of boiler, 

 so that the heat produced from the fuel is not applied in so 

 economical a manner as when large boilers are used. 



That the whole power of the steam cannot be made avail- 

 able, as condensation is impracticable. 



That the engine is confined in all its parts ; the stroke of 

 the cylinders and the connecting rods being too short, so that 

 the friction is much more considerable than in a stationary 

 engine. 



That the steam cannot be made to do its full duty by 

 being worked expansively, as in a stationary engine. 



That as the valve openings must be wide, much steam is 

 lost at each stroke, and rushes into the atmosphere without 

 doing any duty. 



That the pistons of the engine must work at a much 

 greater speed than has been found advisable in the con- 

 struction of stationary engines. 



That the draft of the furnace must be produced at the 

 expense of the power of the engine by contracting the blast 



