354 



Profs. H. T. Barnes and E. G. Coker. 



[Nov. 4, 



method had been applied to the measurement of the lower limit of 

 stream-line flow, and that, from measurements at different tempera- 

 tures, it had been found that the variation with temperature followed 

 the theoretical accurately. 



persecamd 



Z-0 

 1-8 



J'O 



o-S 



0-6 



o-n 



\ 





2 



10 



3o 



fo So 60 



Temperature C. 



100 



The thermal experiments were arranged in the following way : 

 A large copper tank was fitted with a lead pipe, 8 feet long, coiled up 

 in a smooth spiral. One end of the pipe was connected with the water 

 mains, and the other protruded from the side of the tank and passed 

 through a water-bath, 2 feet long, the temperature of which could be 

 regulated at will and maintained constant by a special form of con- 

 tinuous electrical regulator. The pipe was fitted with a glass 

 prolongation, similar to our previous experiments, and a thermometer 

 was used as before. The tank was fitted with an electrical heater, by 

 means of which the temperature could be changed quickly at will and 

 maintained constant. For the low temperature experiments, an ice-and- 

 water mixture was placed in the tank. 



