Bodies ajfetied by Frittion* ijj 
would , when it was juft put in motion, continue that, motion 
without any acceleration, and therefore the accelerative force 
muft then have been equal to the fridion, and not when the 
moving force of 6 oz. was applied. 
From thefe experiments therefore it appears, how very 
considerable the cohefion was in proportion to the fridion when 
the body was in motion ; it being, in the latter cafe, almoft 
i, and in the former it was found to be very nearly equal to 
the whole fridion. All the conclufions therefore deduced from 
the experiments, which have been inftituted to determine the 
fridion from the force neceffary to put a body in motion (and I 
have never feen any defcribed but upon fucli a principle) have 
manifeftly been totally falfe ; as fuch experiments only Shew 
the refiftance which arifes from the cohefion and f rid ion con- 
jointly. 
8. I fliall conclude this part of the fubjed with a remark 
upon Art. 5. It appears from all the experiments which I have 
made, that the proportion of the increafe of the fridion to the 
increafe of the weight was different in all the different bodies 
which were made ufe of ; no general rule therefore can be efta- 
bliftied to determine this for all bodies, and the experiments 
which I have hitherto made have not been fufficient to deter- 
mine it for the fame body. At fome future opportunity, when 
I have more leifure, I intend to repeat the experiments in order 
to eftabliSh, 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 ftiall proceed to eftabliSh 
a theory upon the principles which we have already deduced 
from our experiments. 
V©l. LXXV, A a * R o- 
C 
