[ 36 ] 
4- In like manner, if we take 8"4 for the Sun’s 
parallax, and, thence, his diftance from the Earth 
23468,6 femidiameters of the equator, we (hall find 
that his whole force to produce a difference of Flood 
and Ebb, is to his force at the Earth’s centre, as 1 to 
78234* But the Sun’s diftance being to the radius 
of the Moon’s orbit as 387.34535 to unity, this laft 
force will be to that of the Earth on the Moon, as 
387,34535 to 178.7234 (by cor. 2. prop, princip. I.) 
And the Earth’s force on the Moon is to gravity as 1 
to the fquare of 60.5883 j whence, adding thele 
ratios, the Sun’s force to move the fea will be to the 
force of gravity as the fraction whofe logarithm is 
— 8.1778026 to 1 j or gravity is to that force as 
13249445 to unity. And therefore, by the fame 
analogy as above, we find the difference of Flow and 
Ebb , from the Sun alone, to be 1.97824; one foot 
ill inches. 
The folar force therefore, in raifing the tides, is 
to the lunar, as 1 to 4.4924, in a ratio fomewhat lefs 
than that computed by Sir lj'aac . The ratio likewife 
of the fum of the forces to their difference is but 
7.869 to 5> i n ^ eac ^ of 9 t0 5> which he affumes 
from comparing the Jpring and neap - tides at Brijlol. 
And it is indeed furprizing, how he could, from that 
datum , arrive at conclufions fo near the truth, as his 
very probably are. He tells us he ufed the ratio of 
9 to 5, only till a more certain could be procured, 
And therefore the foreign mathematicians, who have 
cenfured him on that head, and on fome other articles 
of this doCtrine, might have fpared their reflexions ; 
at leaf! till they could fhew that their own deductions 
were more agreeable to nature and obfervation. 
6. Unity 
