PHYSICAL anp LITERARY. 17 
that this proportion of excefs muft be 
multiplied by a number again incompara- 
ble. But this excefs, fo increafed, mutt be 
raifed to a power whofe exponent isa num 
ber equal to the number of all the fixed 
ftars, planets, and comets. And, laftly, 
+f there is an elattic medium diffufed thro’ 
the mundane fpace, as the propagation of 
heat * and many other phenomena feem to 
infinuate; this laft number muft be at 
leat doubled, if we would exprefs the pro- 
portion in which the diftance of the near- 
eft rays exceed the diameters of their par- 
ticles: And yet this diftance of the neareft 
rays, flewing from the fame centre, is fo 
incomparably below our fmalleft mea- 
fares, that there is no poffibility of defi- 
+, 
Uh , 
ey 
4 
. 
ning it. 
6. Hap Euler confidered this extreme ra- 
rity, as well as tenuity of light, which 
mutt be acknowledged by all who fuppofe 
that its particles are actually projected 
from the lucid bedy, he would not have 
alledged, that this opinion is inconfiitent 
f x Il. C : with 
* Nevit. Opt. queries, ad jin. 
