278 Mr. R. Hosking on the 



and 



log«:=7 ; 4282145 ; log /3= 2-5380686. 



All the necessary corrections were made to the readings of 

 the stop-watch, the thermometers, and the pressure-gauge. 

 The flow through the capillary tube was in every case linear, 

 and the kinetic-energy correction comparatively small. 



Care was taken that the liquid should remain free from dust 

 throughout the whole series of observations. The amount of 

 liquid in the glischrometer was so regulated that at each 

 temperature the volume should be unaltered. The obser- 

 vations were begun at low temperatures in every case ; and 

 when the liquid in the glischrometer had reached the next 

 higher temperature, the increase in volume was extracted. 



The air-reservoir was a large copper cylinder connected 

 with a pump on the one side, and on the other side with the 

 manometer and two glass three-way taps, by means of rubber 

 tubing and T-pieces. The two taps were united by rubber 

 tubing to the limbs of the glischrometer, one to each, and the 

 liquid in the glischrometer could be driven in either direction 

 by proper adjustment of the taps. 



The bath was provided with the necessary taps and syphons 

 for filling and emptying it, and, in addition, for running a 

 continuous stream of cold water through the bath for tempe- 

 ratures below the normal. 



The glischrometer, thermometer, and syphon-tubes were 

 kept in position by the cover of the bath, through which 

 suitable holes had been bored. Another hole in the cover 

 admitted the shaft of a small propeller for stirring the water 

 of the bath, with power taken from a small water-motor. 

 When the propeller was rotated quickly by this means, a 

 splendid circulation was set up in the bath. 



In explanation of the accompanying tables, the following- 

 short description of the order of observations may be necessary. 



Imagine that the observations are complete at one tempe- 

 rature, and the bath is being heated to the next temperature 

 at which we desire to make a measurement. 



When this temperature has been reached, the stirrer is set 

 in motion and the regulating flame increased to prevent 

 cooling : when the temperature remains practically constant, 

 the liquid is driven into the right limb by turning the left tap 

 to pressure and the right to air : when the meniscus in the 

 left limb has reached the lower mark, the left tap is also 

 turned to air, and the indiarubber from the top of the 



