60 ESSAYS anv OBSERVATIONS 
experiments; not for confirming himfelf 
im preeonceived opinions, as many do}; 
but for difcovering the true manner in 
which light is: inflected, for producing 
the coloured fringes with black lines be- 
tween then Tie adds, however, fome’ 
queries which contain hints of what he 
had gathered on this fubject from his 
own obfervations, viz. that the rays of 
light differ according to their colour in: 
their degrees of flexibility, and that they 
are bent feveral times backwards and for- 
wards with a ferpentine motion in paffing 
by the fharp edges of bodies: Thefe 
thoughts he threw out “in order to in- 
“‘ cite others to a further fearch*.” But, 
fo far have his intentions been difap~ 
pointed hitherto, that few phyfical writers 
feem to comprehend diftinétly the hints 
which he has left concerning the manner 
of inflexions |; and none, as-far as [know, 
has) 
* Newt. Opt, p, 313. fee the firt two or three que~ 
ries, : 
+ When any opaque body is held at the diftance of 
iree or four inches from the.eye, fo that-a part of fome 
raore: 
