[ 3 21 ] 
have received, appearing by the Grain to be of that 
kind of Wood. 
Laftly, the petrific Juices may happen to be fo 
ftrongly impregnated with Saits and Metal, or any 
other mineral Particles, that they will immediately 
fwell and fill the minuted Pores of the Wood, and; 
by a fudden Coalition, hinder their further penetrating 
into it; which feems to appear clearly from fome 
Cavities in one of thefe Stones* which I fuppofe to 
have been Worm Holes, and which were no way 
filled by the petrefeent Liquor which was flopped 
round it; all the Sides of this Hole being overlaid 
with fmall brown Cryftals, occafioned by the Eva- 
poration of the aqueous Parrs, and their being flopped 
and foaked by the neighbouring Stone or Wood. 
The woody Part of thefe Stones, as 1 have ob- 
ferved, will burn to a Coal, and emit a Flame : That 
Part intermediate betwixt the Stone and Wood, and 
which is but partly petrified, being harder than Wood^ 
and fofter than Stone, will grow red in the Fire, emit 
a kind of Flame, or rather Sparks of Fire, but doth 
not confume, and is properly what Dr. Grew* calls 
incombuftible Wood. The ftony Part doth not burn, 
tho' it grows as red as Coal. 
I calcined another of thefe Stones, weighing 
i oz. is penywts. n^gr. ; after burning' 4 Hours it 
weighed but 1 ez. \openywts . and loft 3 pc- 
nywts. 4 gr, ; which proceeds, I fuppofe, from un- 
petrified Veins of Wood in the Heart of the Stone, 
which were deftroyed by the Fire, as in the Cruci- 
ble it emitted now-and-then a bluifh Flame, as 
Brandy doth when burning. This Stone, when taken 
ST 2 out 
* Muf. R. S . p. 269. 
