on a new Friction Sledge for stopping liailway Trains. 



225 



In this Table v' denotes the velocity of the waggon at the point X, situated 

 11 feet above the sledge; i. e. it is the mean of the initial and final velocities 

 of the shock ; it is computed from the velocity at 0, by adding to its square the 

 square of the velocity due to the space OX, and extracting the square root of 

 the sum. The velocity at O is found from the formula 



„ 200 + -4651 1- 

 2t 

 ill which t denotes the time of describing 00", in Table (1). In Exp. (2) we 

 must substitute 185 for 200 in the formida ; and in Exp. (6), 215 instead of 200, 

 adding, in the latter case, in order to compute v\ the square of the velocity due 

 to 4 feet instead of 11'25 feet 



In the second column, \/s is found from the second column of Table (1). 



In the third column, i' = -9525 v'; the numerical coefficient being deduced 

 from the weights of the waggon and sledge. 



In the fourth column, ?{ = 32"134— "05 v; the coefficients being deduced 

 from the equation which defines u (p. 222). 



Second Series. 



January 26, 1850. — Wet day. 



"Weights of waggon and sledge same as before. 



Table (1). — Original Measurements. 



These experiments were tried in a manner similar to the last six experi- 

 ments of the first series. 



