bodies qff'ecied by Friolf on* ' ' l6^ 



flage Was then adjufted to the fpacp conelponding to 3'', upoti 

 iuppofitioii that the fpaces defcended through were as the 

 fquares of the times, and it was found to agree with the time ; 

 <the ftage was then adjufled to the fpace correfponding to 2'% 

 upon the fame fuppofition, and it was found to agree with the 

 time ; the ftage was then adjufted to the fpace correfponding 

 to i'\ and was found to agree with the time. 



Exp. 4. A fourth body was then taken and laid upon the 

 horizontal plane, and a moving force applied, which defcended 

 '^^ inches in 4^'; the ftage was then adjufted to the fpace 

 through which it ought to defcend in 3'', upon fuppofition 

 that the fpaces defcended through were as the fquares of the 

 times, and it was found to agree with the time ; the ftage was 

 then adjufted to the fpace correfponding to 2^\ upon the fame 

 fuppofition, and was found to agree with the time ; laftly, the 

 ilage was adjufted to the fpace correfponding to i'\ and it was 

 found to agree exactly with the time. 



Befides thefe experiments, a great number of others were 

 ttiade with hard bodies, or thofe whofe parts fo firmly cohered 

 as not to be moved inter fe by the fri£lion ; and in each experi- 

 ment bodies of very different degrees of friclion were chofen, 

 and the refults all agreed with thofe related above ; we may 

 therefore conclude, that thefriSlion of hard bodies in motion is a 

 uniformly r etar ding for ce^ 



But to determine whether the fame was true for bodies when 

 covered with cloth, woollen, &c. experiments were made in 

 ■order to afcertain it ; when it was found in all cafes, that the 

 retarding force Increafed with the velocity j but, upon covering 

 bodies with paper, the confequences were found to agree with 

 thofe related abovft 



Vol. LXXV, Z 4. Having 



