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Mr. W. Ellis Williams on the 



velocity of "13 cm. per sec. in glycerine. Fig. 2 is for 

 a sphere of *8 cm. radius moving in the smaller glass trough, 



Fig-. 2. 



Sphere in glycerine, V«/i>=*0116 (Experimental). 



while fig. 3 is for the same sphere moving in a cubical 

 trough measuring 10 X 10 x 10 cm., this latter being taken 

 for comparison with a theoretical result to be given later. 



Figr. 3. 



Sphere in cube, \a'v—'01l6 (Experimental). 



The kinematic coefficient of viscosity was found to be 10 c.g.s. 

 units, and the value of Vajv is therefore "0116 or rather more 

 than 1 per cent, of the critical velocity. The motion should 



