198 Mr. Bowpnoin on Light, and tbe Wafle of Matter : 
° Tf the calculation, referred to in that paragraph, be juft ; and 
we fhould fuppofe a fingle particle of light, though incompa- 
rably fmaller, to be in bignefs equal to that point, I would atk, 
whether the quantity of matter in fuch a particle would not 
be (mall in a greater degree than its velocity, equal to that of 
the fun’s light, would bé great ? If fo, à particle of light in 
motion, agreeably to the foregoing fuppofition, may be here 
eftimated 6, and its momentum not fufficient to remove the 
lighteft duft ; much lefs’ to do as much execution as a twenty 
four pounder, difcharged'from a cannon. * 
It is: impoflible. to calculate the momentum, where the re- 
quifite data:cannot be had : | but: fuppofing the candle-flame 
equal in bulk to a fphere of half an inch diameter, and to weigh 
as much as an equal bulk of air, viz. about one thirtieth part 
of a grain ; though in fa& its gravity is incomputably lefs than 
that of air: then the {quare áforefaid will exprefs the propor- 
tion, in which the denfity. of the candle-light is diminifhed at 
the verge of the greater circle : and the fame proportion of one 
thirtieth of a grain willexprefs the weight of thatlight at theverge, 
‘VIZ. ONE 30, Fe 280,128,000th part ofa grain ; which we will 
'confider as the weight of a fingle particle of thefun's light. If 
the velocity of light be at the rate of 80,000,000 miles in fix 
minutes, then. its velocity. will be 222,222.miles, equal to 
14,079,985,920 inches, in a fecond.. This number of inches, 
divided by 30,831,280,128,000, the fuppofed particles ima 
grain, will thew the degree of motion required ina body weigh- 
ing one grain to give it a momentum, equal to that of a partir 
cle of light, upon the hypothefis affümed : which motion will 
-be 456 millionth parts of an inch in a fecond, equal to one inch 
im 2190 feconds, or thirty fix minutes and an hut; andis much 
~~ flower 
t 
