Bodies affeSied by FrtSim* 177 



"would^ when It was jufl put in motion, continue that motion 

 without any acceleration, and therefore the accelerative force 

 muil: then have been equal to the fridlion, and not when the 

 moving force of 6 oz. was applied. 



From thefe experiments therefore it appears, how very 

 confiderable the cohelion was in proportion to the frI6i;ion when 

 the body was in motion ; it being, in the latter cafe, almoll: 

 I, and in the former it was found to be very nearly equal to 

 the whole fridlon. All the conclufions therefore deduced from 

 the experiments, which have been inditutcd to determine the 

 fridlion from the force neceflary to put a body in motion (and I 

 have never feen any defcribed but upon fuch a principle) have 

 manifeftly been totally falfe ; as fuch experiments only fhew 

 the refiftance which arifes from the cohefion and fri<Sion con- 

 jointly. 



8. I fhall conclude this part of the fubje£l with a remark 

 upon Art, 5. It appears from all the experiments which I have 

 made, that the proportion of the increafe of the fri(flion to the 

 increafe of the weight was different in all the different bodies 

 which were made ufe of; no general rule therefore can be efia- 

 blilhed to determine this for all bodies, and the experiments 

 which I have hitherto made have not been fufficient to deter- 

 mine it for thofame body. At fome future opportunity, when 

 I have more leifure, I intend to repeat the experiments in order 

 to eftablifh, in fome particular cafes, the law by which the 

 quantity of fridion increafes by increafing the weight. Leaving 

 this fubjed therefore for the prefent, I (hall proceed to eftablilh 

 a theory upon the principles which we have already deduced 

 from our experiments. 



V©L. LXXV. A a PRO- 



