232 



EIGHTH REPORT — 1838. 



nately to the air. The transverse section of these wagons is 

 represented in the annexed figure. The rectangle A B F E re- 

 presents the moveable end, which, when the fi-ontage of thewagon 

 is required to be diminished, is laid flat upon the platform. The 



whole frontage, composed of the rectangle A B D C, and the 

 transverse section of the framing, wheels, springs, and axle, 

 amounts to 47'8 square feet, which, when the high sides are 

 lowered, is diminished by the magnitude of the rectangle ABFE. 

 This latter being twenty-four square feet, it follows that the 

 transverse section with the high sides has very nearly double 

 the magnitude of the transverse section when the sides were 

 lowered. 



Immediately before the experiments, the wagons had been 

 taken a distance of thirty miles, from Warrington to the Made- 

 ley summit,, so that the axles might be expected to be in good 

 running order, and the grease properly melted and supplied. 



The weather was fair and quite dry,' with a breeze from the 

 north blowing almost directly up the planes, and therefore in- 



