Jmkri but was eafie to mclr. This we put into a deep round 
Glafs with a wide mouth, and held it by the fire-fide in a mode- 
rate warmth^till it was brought into a /^/W ftate • then we tranf» 
fer'dicinto on^ of out Pmnwatied Receivers^ where we pre- 
fum'd, that this Temporary Liquor would, as well as Liquors^ 
that are conftandy fuch, difclofe-^^Wrf/^^^^/^'i, when the pref- 
fure of the Air was withdrawn from it ; and accordingly ha^ 
ving caufed the -^ir to be pumpt out by degrees,we found,thaE 
flore of Bubbles appeared at the top of the Liquor, and made 
there a copious Froth , many of them being, by reafonof the 
"vifcopyoi the Fluid, very large, and divers of them, becaufe 
of the Nature and Texture of itand theThinnefsof the films, 
being adorn'd with the colours of the K4i;iW,whofe vividnefs 
made chempleafant tobehold,and fuggefted to Us Tome Optical 
Cbnfiderations. But notwithftanding this Froth, \ caufed the 
pumping to be connnued, that thofe Bubb'cs that had mofl: of 
common Air in them, and which therefore are wont to rife firll; 
might get to the top, and the fubfequent Bubbles might meec 
with more refiftance from the Liquor ftill tending to grow 
cold, and fo might be the more expanded, and yet kept from 
emerging by the concretion of the E^^/i^^ fubftance ; andan» 
fwerably to this we found, thaty when this Subftancehad refui 
med its confiftent form, there were interceptcd,between theup^ 
per and the lower /i^r/k(rr/ of it, fom^ Bubbles that were not 
fmall, which yet had aconfiderable Refleftion, notwithftanding 
the final! quantity of thegrofier Particles of the Air, that may 
be fuppofed to be contained in Bubbles fo very much expand^ 
edj (perhaps fb, as to. exceed fome hundreds of times their 
former Dimenfions.) I might add, that by letting the outward 
Air into the K^mW, the Air in divers of the formerly mentis 
on'd large Bubbles, at the top of the Glafs, was too much rari-* 
fied to keep them from being broken by the preflTureof the 
returning Air. But lam fenfibie, that, in what J have faid of 
the Reflexive power of the Air, I have already too far digref- 
fed, and therefore I fhall ftep into the way again ^ and proceed 
to other Obfervations. 
Jf^/^r being fpconfiderable a Body here below, 1 thought, it 
would be worth while, to endeavour to obferve its ^^^^ 
Surface when contiguous to other Fluids than jlir^ 
and, if it were ppfiible, when furraunded by chenu For though 
