g2 ESSAYS ann OBSERVATIONS 
the matter, and the other from the force of 
cohefion. When an inpreffion is made by 
aftroke, upon the furface of any yielding 
fubftance, fuch as foft clay; the refiftance to 
be overcome in making that imprefiion, pro- 
-ceeds almoft entirely from the tenacity or co- 
hefion: any refiftance arifing from the zvertia 
of the fmall quantity of matter difplaced in 
forming the pit or cavity, is quite inconfider- 
able. The force of cohefion or attraction 
amongft the feveral particles of any homoge- 
neous body, is equal and conftant; and there- 
fore, muft produce an uniform refiftance to 
the motion of any body applied to overcome 
it, or arefiftance proportional to the time of 
the action. The continued refiftance of a 
few attracting particles in a flow motion, and 
the fucceffive refiftance of a greater number 
of particles in a quick motion, will equally 
diminifh the force of a given {pherical body, 
in an equal time. If then the force of any 
ball, moving with a certain velocity, be con- 
fumed by the refiftance from cohefion in a gi- 
ven time; the force of the fame ball moving 
with double velocity, will be confumed in a 
double time; if the velocity be triple, the 
time will likewife be triple; and the veloci- 
ties 
