ABRASION OF THE SURFACeI'oF sbuDS. 



153 



Experiments on the Friction of different Woods two square inches surface. 



Weight 

 on sur- 

 face. 



cwt. 

 1 



2 

 1 



2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 



Weight re- 

 quired to 

 move it. 



Proportion. ^'='g''* P^^-" 



square inch. 



Average. 



Black Beech on Black Beech. 



cwt. qrs. 

 1 



2 



7.13 



Weight 

 on sur- 

 face. 



Weight re- 

 quired to 

 move it. 



Proportion, 



Weight per 

 square inch. 



Average. 



Norway Oak on Norway Oak. 



cwt. 

 i 



2 

 1 



2 

 3 

 4 

 5 



6 



7 

 8 



lbs. oz. 

 8 3 



14 



26 



41 



56 



67 



80 

 102 

 164 3 



6.83 

 7.82 

 8.53 

 8.17 

 7.93 

 8.33 

 8.37 

 7.68 

 5.45 



cwt. qrs. 



1 



2 



7.67 



English Oak on English Oak. 



Hornbeam on Hornbeam. 



cwt. 

 i 



2 



1 

 2 

 3 

 4 

 5 



cwt. qrs. 





 



1 

 1 



2 

 2 



7.83 



cwt. 

 X 



2 

 1 



2 

 3 

 4 

 5 

 6 

 7 



lbs. 

 8 



16 

 30 

 46 

 65 

 83 

 105 

 167 



oz, 

 10 

 3 

 5 

 11 

 5 

 1 



6.49 

 6.91 

 7.38 

 7.19 

 6.85 

 6.74 

 6.39 

 4.68 



cwt. qrs. 



6.57 



Elm on Elm. 



Honduras Mahogany on Honduras Mahogany. 



cwt. 

 I 



2 



1 



2 

 3 

 4 

 5 



6 



7 

 8 



cwt. qrs. 

 1 



2 



5.86 



Yellow Deal on Yellow Deal. 



cwt, qrs. 



2.88 



cwt. 

 I 



2 

 1 



2 



3 



4 



5 



6 



7 



8 



9 

 10 

 11 



cwt. qrs. 





 

 1 



1 2 



2 







5.96 



White Deal on White Deal. 



cwt. 

 1 



2 

 1 



2 



lbs. oz. 



18 12 



29 5 



48 3 



2.98 

 3.82 

 4.94 



cwt. qrs. 

 1 



2 



1 



3.81 



MDCCCXXIX. 



