Opticks 1717 - Up

tiltervals caukd by interjncent Ais? as the Sines
ar- wllich meafurc the Refia@on made out of
f&g Medium into Air.
04J; II. When the Warer was between the,
~l&s, if I prclibd tl?e upper Glafs varioufly at
its edges to make the Rings m&e nilnbly from
(911e place to al~otll~~l > ‘, a lildc wl-lit,c Spot would
ihrnediately ~OIIOW the ccnt.cr of thcln, whicl~
~pll creeping in of the anibient Water ,into that
place would prefcntly varkifk. Its appearance
was fuch as intcrjaccnt Air would have caufed,
and it exhibited the fame Colo~p., But it was
not: Air, fbr where any I3ubbles ofAir were in
t,he Watts they would 110 t vanitir’ 3%~ Reflexion
multi have rather been caufed by a iizbtikr
Medium , whkh co~ild reccdc through the
Glaf‘es at the creeping in of the W ~tcr.
CUT IZa Thefe OI$crvations wcse made in
the open Air. 113,ut f-$rthcr, to exntnine the Effix%
‘of ~o~our!ci Light fa@g on the GMFe$ I
d~&2Il’d the :R,oom, and VLCW’d tlmn by Reflcxion
of the