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rical furface A BCD ; and the folid fpace contained 
between them is very nearly equal to a cylinder, upon 
a bate equal to the fpherical furface ABCD, and of 
altitude equal to e f. Therefore diminifh the dia- 
meter of each particle of light, that is, diminifh e in 
any proportion whatfoever, and the folid fpace ABCD 
XeJ diminifhes in the fame proportion. And if the 
matter in that fpace were given, the denfity of it 
would always be as But the matter of each 
particle of light, and confequently the matter of the 
given number in the fpace ABCD x is always 
as ef*. Therefore the denfity of the fubftance 
formed by light in the fpace ABCD x ef is always 
ef 3 rz 
as or as ef . 
e J 
That is, the number of fpherical particles of light, 
in the folid fpace ABCD xef, being given, and the 
denfity of each particle, and the fpherical furface 
ABCD being given, the fquare of the diameter of 
each particle will be as the denfity of the fubftance 
they compofe, upon the furface of the fun. But it has 
been found, that if the diameter of each fpheruie 
were one millionth of one millionth of an inch, the 
greateft number of fuch fpherules, that the fun’s 
furface can contain at once, would, with the denfity 
which has been afiigned to each feparate particle, 
form a fubftance upon it i 2 times more denfe than 
water. Therefore, that the fame number of fuch 
particles fhould form a fubftance about 173 times 
Jefs denfe than water, the. diameter of each mult 
not exceed J * th of one millionth of one 
4-5 6 
millionth of an inch. But I have fhewn that the 
