MECHANICS. 



27 



TABLE II. Friction of Rollers of Lignum-vitce of six inches and two inches 

 diameter. Pressure 1. 



" We shall next present the results of 

 Coulomb's experiments upon the ri- 

 gidity of cords, and different rollers be- 

 tween 2 and 12 inches in diameter; the 

 deduction for the friction is stated in 

 the table, and a comparative column 

 exhibits the rigidity deduced from the 

 experiments made with the apparatus 

 of Amontons. The cords were of three 



kinds: No. 1, of 6 threads in a yarn, 

 or 2 in a strand, the circumference 12 

 lines, and weight of a foot in length 4| 

 drachms. No 2, of 15 threads in a yarn, 

 or 5 in a strand, circumference 20 lines, 

 weight of a foot in length 12 drachms. 

 No. 3, of 30 threads in a yarn, or 10 in 

 a strand, circumference 28 lines, weight 

 of a foot in length 24 ^ drams. 



TABLE III. Rigidity of Cords. 



" From this table it will be seen that ences, where greatest, to the circum- 



the method of Amontons and that of stances of the cords having been more 



Coulomb furnish nearly the same re- used previous to their being taken for one 



suits : M. Coulomb ascribes the differ- kind of experiment, than for the other." 



