﻿by Change in Angular Velocity. 9 



experiments, the results given here are based on 215 distinct 

 experiments. 



In taking the stop-watch readings, disturbances of the 

 circular motion of the lycopodium owing to turbulence 

 or eddying were avoided as much as possible, and selections 

 were made of those motions which lay most nearly along 

 the circle considered. This means that when turbulence 

 is increased, the angles through which the particles are 

 timed become less. The effect of the turbulence is merely 

 to broaden the band of points, but the mean motion, repre- 

 sented by the median line, is always well-defined. 



§ 4. Discussion of Results. 



The results obtained are embodied in the accompanying 

 curves. These are derived from the observational curves 

 mentioned in § 3. The following reference table explains 

 the figures : — 



Stopping. 



Starting. 



Stopping. 



Starting. 



Stopping. 



Starting. 



Stopping. 



Starting. 



Stopping. 



Starting. 



Stopping. 



Starting. 



Stopping. 



Starting. 



Stopping. 



In these figures each curve represents the distribution of 

 angular velocities </}/£! over a radius of the cylinder at 

 the time vtjc 2 corresponding to the number given alongside 

 the curve. The times in seconds corresponding to these 

 numbers may be obtained by use of the following table, 

 the water being at 17° C. : — 



c l = 2'40 cm. vtjc 2 = '01 corresponds to /= 5*30 sees. 

 c 2 = 7-48 „ vt/c 2 = -01 „ „ t= 51-8 „ 



c 3 =12-69 „ vt/c 2 = '()l „ „ t= 148-4 „ 



.4. 



Cl =2-40 



cm. 



n 2 =10 r.p.m. 



5. 



•>•> 





I2 3 = 36 



6. 



?5 





£2 3 = 36 „ 



7. 



c 2 = 7*48 



cm. 



n t = n „ 



8. 



>y 





n,= ij „ 



9. 



55 





G 2 =10 „ 



10. 



;? 





n 2 =io „ 



11. 



5> 





n 3 =36 



12. 



?5 





X2 8 =36 



13. 



c 3 = 12-69 



cm. 



Gi= H » 



14. 



?i 





n,= ii „ 



15. 



?5 





n 2 =io 



16. 



•>y 





n 2 =io 



17. 



5? 





n 3 =36 



18. 



J? 





123 = 36" 



