PHYSICAL aNnp LITERARY. 81 
jooks blueith ; and at twenty or thirty, e 
{pecially if the air be thickened, degene- 
fates into a dim white, fo that one can 
hardly diftinguifh it from the clouds that 
fkirt the horizon. With refpect to the 
primary planets, it may be likeways an- 
{fwered, that perhaps we fee them chiefly 
by light reflected from the air and va- 
pours that furround them. 
‘Quer, XIE Wuy is it fo hard to di- 
ftinguifh green bodies from blue “8 can- 
dle-light? 
Quer. XIV. WHENCE proceeds the 
bluenefs of the fey? Since it is certain 
that no body affumes any particular co 
lonr, but becaufe it reflects one fort of 
rays more abundantly than the reft; and — 
fince it cannot be fuppofed that the con- 
flituent parts of pure air are grois enough 
to feparate any colours of themfelves ; 
sli we not conclude, with Sir Ifaac New: 
ton * , that the violet and blue making 
rays are reflected more abundantly than | 
the reft, by the finer vapours ‘diffafed 
Vou. H. L.: through 
# Opt. book 2. part. 3. prop. 7: 
