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MR. RENNIE'S EXPERIMENTS ON THE FRICTION AND 



The apparatus employed in performing the experiments on the friction of 

 attrition, Plate IV, consists simply of a strong table accurately made and ad- 

 justed, and provided with a platform capable of being elevated to any angle 

 within thirty degrees, as shown by the graduated arc. The substances tried 

 were placed on the platform and in the sliding block above, to which the scale 

 and weights for bringing the substances into closer contact were suspended : 

 a cord going over a pulley was attached to the sliding block, which received its 

 motion from weights put into the moving scale. The different phsenomena were 

 then accurately recorded, as appears by the accompanying Tables, and the 

 conclusions derived from them. 



Table I. 

 Experiments on the Friction of 3 square inches surface with Cloth. 



