Bo^iei affeSied by FriSiion. 1 6*r 



^dly, IV h ether the fridiion varies in proportion to the prejfure 

 ar izj eight. 



4thly, Whether the friclion be the fame on 'whichever of its fur- 

 faces a body moves, , , ■ 



The experiments, in which 1 was alliited by my mgenious 

 friend the Rev. Mr. Jones, Fellow of Trinity College, were made 

 with the utmoft care and attention, and the feveral refults 

 agreed fovery exa6bly with each other, that I do not fcruple to 

 pronounce them to be concluiive. 



. .SCI.; 



2. A plane was adjufted parallel to the horizon^ at the extre- 

 mity of which w^as placed a pulley, which could be elevated or 

 dep relied in order to render the firing which connected the 

 body and the moving force parallel to the plane. . A fcale accu- 

 rately divided was placed by the fide of the pulley perpendi- 

 cular to the horizon, by the fide of which the moving force 

 defcendedi upon the fcale was placed a moveable ftage, which 

 could be adjufted to the fpace through which the moving force 

 defcended in any given time, which time was meafured by a 

 well regulated pendulum clock vibrating feconds. Every thing 

 being thus prepared, the following experiments were made to 

 afcertain the law of friction. But let me firfl obferve, that if 

 fridion be a uniform force, the difference between it and the 

 given force of the moving power mufl be alfo uniform, and 

 therefore the moving body mufl defcend with a uniformly ac- 

 celerated velocity, and confequently the fpaces defcribed from 

 the beginning of the motion mufl be as the fquares of the 

 times, jufl as when there was no fridion, only they will be 

 diminifhed on account of the fridllon. 



3. Exp. I. A body was placed upon the horizontal plane, 

 and a moving force applied, which from repeated trials was found 

 to defcend 52I inches in 4'^ for by the beat of the clock and 



7 ^^^ 



