( 6 {3 > 
fented in the Fig ,) This therefore being i©", z,AC will 
be to AB, that is, the Velocity of Light to the Veio- 
city of the Eye (which in this Cafe may be fuppofed 
the fame as the Velocity of the Earth’s annual Motion' 
in its Orbit) as iono to One, from whence it would 
follow, that Light moves, or is propagated as far as 
from the Sun to the Earth in 8' ii". 
It is well known, that Mr. Romer , who firft attempted 
to account for an apparent Inequality in the Times of the 
Eclipfes of Jupiter * s Satellites, by the Hypothefis of 
the progrdliye Motion of Light, fuppofed that it fpent 
about iT Minutes of Time in its Paffage from the Sun 
to us : but it hath fince been concluded by others from 
the like Eclipfes, that it is propagated as far in about 
7 Minutes. The Velocity of Light therefore deduced 
from the foregoing Hypothefis, is as it were a Mean 
betwixt what had at different times been determined 
from the Eclipfes of Jupiter's Satellites. 
. Thefe different Methods of finding the Velocity of 
Light thus agreeing in the Refulr* we may reafonably 
conclude, not only that thefe Fhawomena are owing, 
to the Caufes to which they have been afcribed • but 
alfo, that Light is propagated (in the fame Medium ) 
with the fame Velocity after it hath been reflected as 
before : for this will be the Confequence, if we allow 
that the Light of the Sun is propagated with the fame 
Velocity, before it is refle&ed, as the Light of the fixt 
Stars . And I imagine this will fcarce be. queftioned, 
if it can be made appear that the Velocity of the Light 
of all t!i ejfxt Stars is equal, and that their Light moves 
or is propagated through equal Spaces in equal Times 
at all Difiances from them: both which points (as I ap- 
prehend) are fufficiently proved, from the apparent Alte- 
ration 
