128 SEC. 4. KINEMATICS, STATICS, AND DYNAMICS, 



d. A pair of iron rollers. 



e. A pair of brass rollers. 



Institute for Physical Science of the University of 

 Giessen ; Professor Dr. Bujff. 



This apparatus was originally used for measuring gliding friction. It is at 

 the same time a convenient appliance for demonstrating the friction of the 

 steam engine on the railway line. 



