A. S. Kimball— Laws of Friction. 357 



not undertaken. Several tables will be given to illustrate the 

 method of conducting a series of experiments with this appa- 



Table V. 



Wrought iron shaft, 1" diam. ; box, cast iron, W long; load, 100 lbs. 



Shaft well oiled. 



Velocity of the circumference of the shaft. 



No. ], 72". No. 2, 272". No. 3, 605". No. 4, 1320". 

 Scale readings 515 500 



Mean 



Position of equilibrium 464 464 464 464 



"Deflections 55 33 22 16 



-Relative values of the coefficient of friction. 



No. 1, 1-00. No. 2, "60. No. 3, -40. • No. 4, -29. 



The results given above were made with high velocities, and 



show coefficients of friction decreasing as the velocity increases. 



.The results of a similar series with very low speeds are 



?iven in the next table. 



Table VI. 



Velocity of the circumference of 

 •02**; No. 3. -060"! No, 





To. 1, -007'; No. 2, 

 _ . 3^-060'; No. 4, -132' in a minute. 

 No. l, -37. No. 2, -51. No. 3, -73. No. 4, TOO. 



These results, unlike those of the former table, show a coeffi- 

 cient of friction increasing as the velocity increases. 



A large number of experiments similar to those given above 

 have been made with uniform results. 



