Profs. H. T. Barnes and E. G. Coker. [Nov. 4, 



Temperature Effect on the Upper Limit by the Thermal Method. 



In Table I we give the series of experiment obtained for the effect of 

 temperature on the upper limit for our smallest brass pipe, 1-05 cms. 

 in diameter. The results are worked out for each point, correcting the 

 volume of the water in the measure to the volume at the temperature 

 of efflux from the tank. The velocity of efflux was then calculated in 

 the usual manner. In fig. 2 we give a plot of the observations, which 

 extended from 1586. Unfortunately, we were unable to extend 

 below 15, on account of the temperature of the water in the mains not 

 being below that at the outset of the experiments. During the time of 

 the experiments, June and July, after the beginning of the hot weather, 

 the temperature steadily rose in the mains to as high as 20, where it 

 stayed during the remainder of the work. 



Table I. 

 D = 0-0105 metre. 



Vc in metres 

 per second. 

 1-146 

 0-677 

 0-789 

 0-905 

 1-088 

 1-091 

 0-421 

 0-466 

 0-137 

 0-259 

 0-512 

 1-091 

 1-149 

 1-401 



In Table II we give Reynolds' observations for his two smaller pipes, 

 the diameters of which lie just above and below our pipe. These tests 

 were made with colour bands. In the last column we reduce the 

 observations to a pipe equal in area to ours, by the simple ratio of the 

 diameters. In the plot we have included Reynolds' observations, and 

 indicated them by circled crosses. We have, also, included the 

 temperature law of Poiseuille. 



