260 



REPORT — 1841. 



A train of eiglit carriages, weighing gros.s 40'75 tons, was dismissed from 

 the top of Madeley Plane,"both with the pointed front and the flat front ; see 

 Tables IX. and X. ~ 



The following is an abstract :- 



The difference is only eighty yards in a distance of eight miles, and the 

 other differences also far too small to establish any actual difference in the 

 resistance. 



The pointed prow was next applied to a train of three carriages, weighing 

 gross l-i'S tons. This train was dismissed four times down the Sutton Plane. 

 In the first and last trips the train descended without having the prow 

 attached either before or behind, and in its ordinary state. In the second 

 trip the prow was fixed behi7id the last carriage ; in the third trip in front of 

 the first carriage. The weather was perfectly fine and calm. The following 

 results are abstracted from Tables I. II. III. IV. in the Appendix : — 



The differences are extremely slight, and such only as would have taken 

 place with the same experiment repeated twice over. The pointed prow was 

 placed at the back of the train, to test an opinion expressed by several indi- 

 viduals who were interested in the inquiry, that the resistance would in some 

 measure be found to depend upon the shape of the hind surface of the last 

 vehicle, and that if the end were pointed, the air would quickly and gently 

 slide into the space just before occupied by the train, without causing so great 

 a relative vacuum. The experiment showed that the pointed prow, whether 

 placed behind the last carriage, or before the first carriage, exercised no 

 appreciable influence on the rate of the train's motion, or on the resistance 

 of which that motion was the index. 



The next subject of inquiry was, whether the circumstance of the car- 

 riages being sent with their square ends foremost, instead of being preceded, 

 as they usually are, by the engine and tender, Avas likely to throw any doubt 

 upon the correctness of the values of resistance determined heretofore for 

 the several trains of carriages. 



tA 



