Opticks 1717 - Up

C 2 311
firaitncfs of the Nledium pent in on 311 fide5
~yiihiil iirch Corpui’cles may n little alter its hIof-ions
or other qualities 011 which the Kcf-lcxion
depends. ULlt yet I CiIllllOt ~~IL,lCll fLlj~& the
laft, becaufe I have obfcrvcd of lome iinall
Plates of Mufcovy Glafs which wcrc of an even
thicknefs, that through n Microi‘cope they have
appeared of the fame Colour at their edges and
corners where the included R/Iedium 117x terminatcd,
which they appeared of iii other p1;1-
cm. Hon~ever it will add much ‘to our SatiTf&ion,
if thofe Corpui’cles can be difcover’d
with Microrcopes ; which if we fllall at length
attain to, I fC!ilS it will be the utnloiE improve3
rnent of this Seiife. For it fccnx ilnpotlible
to fee the niorc i‘ecrct and noble \1~orks of hia-’
ture within the Corpukles by rc~fon of their
tra11~pparc11cy.
P li 0 J?: VIII.
HI S will appear by the following Confidcritions.
Firfk, That in the xflhge of
t out of Glafs into Air there is a k +x&n
as ftrong as in its paEige out of Air illto GlidS,
or rather a little itronger, and by mnn~~ degrees
fironger than in its pafigc Out of Glak into
Q’ater.. And it feems not probable that Air,
fllould have more :ef-letiing parts thim Water
OS Glafs. But if that fllould poITib!y be fuppo-
. fed, yet it: will avail nothing ; for th: Rcflexiorr
. is