Cooling of Cylinders in a Stream of Air. 



121 



The condensed water was collected in a beaker placed 

 underneath the tubes, a glass funnel being attached to the 

 bottom end of the copper tube to ensure that all the con- 

 densed water should be caught in the beaker ; the excess of 



Fig. 2. 



Fig. 3. 



steam which came out with the condensed water escaped to 

 the air past the sides of the tube. The end of the copper 

 tube and the funnel were covered with cotton-wool. A wooden 

 box was built round this receiving apparatus beneath the 

 wind-channel, to shield it from air currents produced by 

 the fan. 



The experiment was carried on in the following manner. 

 The water was boiled and the steam allowed to pass through 

 the copper tube for about five minutes, to ensure that the 

 steady temperature had been attained. 



The first reading of the Pitot-tube was taken, the motor 

 started, and after a short interval, a weighed beaker was 

 placed underneath the end of the cylindrical tube, and the 

 stop-watch started. Readings of the water " head " in the 

 Pitot-tube gauge were registered, and after 10 minutes the 

 beaker was taken away, and the motor stopped. The second 

 zero of the gauge was taken, and the beaker and water 

 weighed. The temperature of the air and the atmospheric 

 pressure were also taken. 



Phil. Mag. S. fi. Vol. 31. No. 182. Feb. 1916. K 



