[ 419 ] 
I fuppofe the denfity of each particle three times 
that of iron b . The number of fuch fpherules that 
contain as much matter as an iron ball of one yard 
diameter, I have found to be 1 5552 xxxvi cd j con- 
quently 576 xxxvi fuch fpherules contain as much 
matter as an iron ball of 1 foot diameter. 
Let fuch a ball be fuppofed to move uniformly 
with a velocity that fhould carry it 1000 yards in 1". 
The light of the fun traverfes the femidiameter 
of the orbis magnus in 7 ' nearly. 
In the enfuing calculations, I lhall reckon the fun’s 
horizontal parallax g". 
According to this hypothecs, the femidiameter of 
the orbis magnus will contain 22919 femidiameters 
of the earth. 
In 1" of time, light, according to the velocity af> 
figned to it, traverfes of this fpace, or 54,57 fe- 
midiameters of the earth, or 381092323 London 
yards. 
Hence the velocity of each particle of light, will 
be to that of the iron ball moving 1000 yards in 
1" as 381092 to 1, very nearly. 
And the ball being 1 foot diameter, it has been 
(hewn that the matter in each particle is to the mat- 
ter in the ball, as 1 to 576 xxxvi. 
Hence the force of the motion in each particle of 
light, is to the force of motion in the ball as 381092 
to 576 xxxvi j that is, as 1 to 151 1444 xxvii, or, 
k Inftantaneous Product. &c. p. 30. 
• Ibid. 
4 The Roman numerals placed after the Arabic chara&ers, 
denote the number of zeros that muft be added to the Arabic 
figures, to compleat the expreffion of the number intended. 
Hhha 
it 
