the abfence and return of the Ambient Air, ss might with any 
probability have the lofs or recovery of the Woods fplendour at- 
tributed to it. For I had formerly (if I were not miftaken) fouad 
by feveral circumftances, which I fhall not now ftay to name, 
That a flight (fo it bean apprppri-ated) variation of the Texture 
of this Wood, and which may feem mainly to refped the Pores 
(v^'hich perhaps ought to be of a determinate (hape and fize, and 
filled with a determinate matter) will have a great operation up- 
on its fplendour. And I formerly found by other trials, that 
even confiftenc Bodies, if foft ones, may have their Pores en- 
larged and vitiatedjand their feulk,and confequently their texture 
(at leaft as to their pores)manifeftly enough altered by having the 
Air withdra'^n from about them (whereby the Aerial pxrticles 
within them were enabled to expand themf€lves)and let ia agiin, 
whereby, as to fenfe, they feemed pretty well reftored to their 
former ftate. But the (ucccfsof my endeavours eicher with Micro- 
/w^/ (through which a vivid piece of Wood will fhine by its 
owsJight) or otherwife, was not confiderable enough to deferve 
a particular account 5 efpecialiy in this Paper, where 1 am not 
to -venture at matter of The$rj. 
Experiment VI. 
THinking fit to try, Whether a/»^ii// quantity of Air, with- 
out being ventilated or renewed, might not fuffic« to 
maintain this Cold fire, though it will not that of a Live Coal, 
or a piece of Match, wecaufed apiece of fliining Wood to be 
JJermetically fealed up in a pipe of clear and thin glafs : but 
though, carrying it into the dark, we found it had quite loft its 
light, yet imagining that that might proceed from its having 
been bver-heated (being fealed up in a Pipe not long enough to 
afford it a due diftance from the flame of the Limp we. employed 
to fealit,) we caufed two or three pieces of frefh Wood, amount- , 
ing all of them to the length of about two inches, to be fealed up 
in a flender pipe between four or five inches in length 5 which be- 
ing warily done, the Wood retained its light very well, when the 
Operation was over: ^^nd afterwards laying it by my bed-fide, 
when the Candles were arried away out of the room^ I coriti- 
d^red 
