refl 5 having drawn out the Air^ all the others dif-appearecJ, 
and even the formerly brighter ones ihone but faintly, when t he 
Pneumatical glafs feemed to be exhaufted. But keeping thein- 
ciuded Body a while in that uofriendly piace^ we perceived the 
parts, that had retained light, to grow more and more dim^ fome 
of them dif appearing, and that, which was formerly the moPc 
confpicuous, bdcignowbutjuft vifible to an attentive Eye, mi 
chat fcarce without difptite.For^if we had not known beforehand, 
that a ftiining matter had been included in the Receiver ^ perhaps 
' we (liould not have found it out. And he that had the youogeft 
Eyes ia the company could not at all difcern it : (the Air being let 
in, the Body began to fliine again.) But this being a fuigle Tml^ . 
which thelatenefs of the night hindred us frore reiterating, is to 
be further profecuted, and in differing fubftaoccs^ before much 
be built upon it^ 
'Experiment V. 
THe RdrefaBm or Expanfion of the Air bavLog fo notable ■ 
an operation upon ourfliining Wood, I thought it would 
not be amifs to try, what the Comfref im of the Air would do to 
ic. For which purpofe we included a piece of it infuch a little 
Idftrument to compreffe, which you may remember to have been 
devifed and propofed by M. Hook, But though we impeli'd the 
Air forcibly enough inta the Glafs, yet, by reafon of the thick> 
nefs~ requifite in fuch GlafTes, and the opacity thence arifiog^ we 
we re not able ^A^;^, to determine whether or rio any change was 
made in the iumiiioofnefs of the Wood, 
Which I thought the lefs ftrangej-becaufe by fome Experi-^ 
meats purpofely devifed (at one of which I remember you were 
prefenty I hid long fince obferveJ, Thsteven a great preffure 
from a fluid Body, which preffeth more uniformly againft all the 
Parts, it toucheth of the conliftent^ody, does work afar lefs 
masifeft change even on foft cr tender fubftanceSjthiaone would 
expe^i from the force wherewith it comprelTeth, 
And were it not, that one contrary oftentimes minds us of aa-^ 
other, I might have forgot, that I had divers thoughts abous 
finding fome good ways of Trying, whether any fech changeof 
Tcxi^ure mighti>e difcoveied to be aiadein the fliining Wood by . 
