152 



MR. RENNIE'S EXPERIMENTS ON THE FRICTION AND 



Table III. On the Friction with Cloth at different angles of elevation. 



1. In comparing the results given by the angles of repose with the results given by the horizontal 

 surfaces on similar kinds of cloth, there is a slight variation. 



2. The second series of experiments afford no measure of comparison, from the inadequacy of the 

 weights of lOlbs. being unable to give motion to the upper surface, 13lbs, 8oz. gives an approximation. 



3. The less the weight, the greater the angle of repose. 



4. Increase of surface produces a very great increase in the angles of repose. 



The times very variable, diminish with increase of weight. 



5. Velocities likewise variable. 



Table IV. On the Friction of different Woods two square inches surface. 



Weight 

 on sur- 

 face. 



Weight re- 

 quired to 

 move it. 



Proportion. 



Weight per 

 square inch. 



Average. 



Red Teak on Red Teak. 



cwt. 

 I 



2 

 1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



cwt. qrs. 

 1 

 2 



2 



2 2 



8.82 



Pine on Pine. 



cwt. 

 I 



2 

 1 



2 

 3 



lbs. oz. 

 16 3 

 27 14 

 68 4 



111 5 



3.33 

 4.01 



3.27 

 3.01 



cwt. qrs. 



1 



2 



1 



1 2 



3.40 



Weight 

 on sur- 

 face. 



Weight re- 

 quired to 

 move it. 



Proportion, 



Weight per 

 square inch. 



Average. 



American live Oak on American live Oak. 



cwt. 

 I 



2 

 1 



2 



3 



4 



6 



6 



7 



8 



9 



10 



11 



12 



7.65 



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