needful to preferve the material Syfem: — .— aa: 
intimate fome peculiarity in their pendens ce andi in fee P 
cumftances attending them. 
"Nature thus exhibiting, on a Broad (cale, bdo, eaae 
our little experiments can exhibit only in miniature ; and of 
which thofe experiments fometimes lead. to a happy NEM 
tion. 
Whether the foregoing be fuch an explanation, Gr sal 
i Samp in reference to the colour of the-expanfe, does not 
affect the expanfe itfelf : whofe exiftence, confidered as an all- 
furrounding orb, may be real, although the affigned: caufe ot 
its colour be demonftrably without foundation. P i 
From the feveral phenomena above-mentioned, unlefs! he 
evidence fuppofed to arife from them be futile, or inadmiffible, 
there is reafon to: conclude, that am all- forrounding orb rji 
really exift ; and that the blue expanfe is that orb. SP 
It is an obfervation of Sir J/aac Newton, ** that the di 
finefs of natural. philofophy, is to argue from phenomena, with- 
out feigning hypotheíts ; and to deduce caufes from effects, 
till we come to the very firft caufe, which certainly is not mè» 
chanical ; and not only to unfold the mechanifm of ie MeL 3 
but chiefly [among others that are mentioned} torë 
and fuch like quettions, viz. Whence is it, that the fun m 
planets: gravitate tow ards one another, without denfe triatter be | 
tween them ?- HE ioc sapien ue fit fürs P Fron filling. oe 
one another P* a | 
-Agreeably to ke e RI 6 obfervation; the” ‘author " this 
p i n adduced certain phenomena, he hopes’ not im- 
pertitiéritly, has endeavoured; not only to argue from eher; aid. 
tə pu the caa from the 'effe&ts; but t6 refolve: siga 
queftion - 
* Opticks: p.344. 4th edit. 8vo. 
