the sudden Expansiori of compressed elastic Fluids. 249 



increase of 20° of temperature at that end of the copper pipe. 

 The tube being removed, another copper tube C (fig. 2.) of 



Fig. 2. 



-^ 



F 



the same diameter, and nine inches long, was screwed to the 

 same cock B. This tube was furnished with a thermometer 

 D as in the last experiment. The end E of the copper tube 

 was stopped by aflat plate, excepting a hole l-12th of an inch 

 diameter, in the centre of the plate. The steam in the boiler 

 being about the same force as in the last experiment, and the 

 cock B being opened, the thermometer D stood at 292° ; 

 while another thermometer, having a very small bulb, held 

 near the hole at E, as the steam issued from it, stood at 185°. 

 A small glass tube F, open at both ends and drawn to a fine 

 point at the top, was placed so that the top of the tube was in 

 the jet of steam issuing from E, while the lower end of it 

 was immersed in a trough of mercury. The thermometer D 

 standing at 292°, as before, the mercury rose twelve inches 

 in the tube F. The mercury stood highest in F when it was 

 near to E. 



In August 1825, I had an opportunity of making some ex- 

 periments on the sudden expansion of atmospheric air at Messrs. 

 Fairburn and Lillie's foundry in this town, of which the fol- 



N. S. Vol. 5. No. 28. April 1829. 2 K lowing 



