OF THE CRITICAL VELOCITY OF WATER WITH TEMPERATURE. 
61 
observations in the neighbourhood of 30°, for the experimental results on stream¬ 
line motion are probably less accurate, as was pointed out in a previous section. The 
law of variation is found to be approximately 
v-^ a: I + 0-03368T + -0001561^ 
which agrees very closely with the variation in the viscosity of water, viz., 
^-1 oc I + 0-03368T + •000221Tb 
It may therefore be concluded that for small pipes, over the range of temperature 
examined, the critical velocity of water varies directly as the viscosity. 
In conclusion the authors desire to thank Professor Bovey for placing the 
hydraulic laboratory of McGill University at their disposal, and also L)r. Barnes, 
who gave much assistance during tiie progress of the work. 
25 MAA1903 
