Cooling of Cylinders in a Stream off Air. 



129 



Fig, 6. 



I. The values o£ n obtained were : — 



(1) n = '67, 



(2) n = -62, 



(3) n = -61. 



These results show that the heat lost from the stream-line 

 tube is slightly greater than that lost from a circular tube of 

 same total area, but much greater than from a circular tube 

 of the same width or same air resistance. This will be more 

 dearly shown by the following comparative values. 



(1) Heat-loss from stream-line tube at velocity 13 metres 

 per sec. = 1735 cals. per cm. length. 



(2) Heat-loss from cylinder of same diameter as the 

 maximum thickness of stream-line tube at velocity 

 13 metres per sec. = 695 cals. per cm. length. 



(3) Heat-loss from a cylinder of the same total area 

 (7*3 cm. diam. approx.) =1476 cals. per cm. length 

 at velocity 13 metres per sec. 



(4) Heat-loss from cylinder of the same air resistance as 

 stream-line tube (^ diam. = *3 cm.) at 13 metres per sec. 

 = 233 cals. per cm. length. 



The curves in fig. 6 also show that the cooling is much 

 greater when the stream-line tube is placed in position (2) 



