78 



REPORT — 1859. 



descended a previously measured distance with a uniformly accelerating 

 velocity, they passed over a detonating signal which conveyed notice to the 

 guard to put on the breaks. Then the train having been brought to a stand, 

 the distance from the fog-signal to the point at which the train stopped was 

 measured, and the train brought back for another experiment. In this way 

 it was easy to obtain an initial velocity of 50 feet a second, or 35 miles an 

 hour before applying the breaks. 



Unfortunately the day upon which these experiments were made proved 

 misty and foggy with rain at intervals, so that the rails were in the very worst 

 condition for facilitating the stoppage of the train. The significance of this 

 fact will be seen on comparing the retarding power of the breaks in these 

 experiments with those made in fine weather. 



Reducing the results, we find that the retarding force exerted by each 

 break in terms of a unit of mass, calculated from the distance of pulling up, 

 was equivalent to the numbers in the following Table : — 



Experiments on the Oldham Incline. 



The general result of these experiments gives a retarding force of 1'74 lb. 

 per unit of mass for Mr. Newali's break, and 1*85 for Mr. Fay's; or in other 

 words, Mr. Newali's break exerted a retarding force of 121-3 lbs. per ton 

 weight of the train, and Mr. Fay's a retarding force of 129 lbs. per ton. 



I afterwards arranged for some further experiments at Southport upon a 

 piece of level rail between that town and Liverpool. The speed requisite in 

 this case had to be obtained by the aid of an engine which was detached by 

 a slip coupling at the instant of applying the breaks. In other respects these 

 experiments were conducted like the preceding with fog-signals, and the time 

 noted by stop-watches. The weather, however, was in this case fine and dry, 

 and hence the following results were obtained in the most uniform circum- 

 stances. 



The friction of the train itself, and the resistance of the air, were ascertained 

 to amount with Mr. Newali's train to 6*4 lbs. per ton, and with Mr. Fay's 

 train to 10*4 lbs. per ton. 



In this case we have a retarding force per unit of mass equivalent to 5"49 

 lbs. in Mr. Newali's break, and 6 7 lbs. in Mr. Fay's ; or in other words, 

 the retarding force of the slide breaks of Mr. Newall, from eight experiments, 

 at velocities varying from 35 to 60 miles an hour, was equivalent to 382*6 lbs. 

 per ton weight of the train. 



The retarding force of Mr. Fay's slide break from eight similar experiments, 

 at velocities varying from 33 to 63 miles per hour, was equivalent to 466'4 

 lbs. per ton weight of the train. 



