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Thcfe kind of Petrifications generally ferment with 
Acids and Spirit of Vitriol, and, by Calcination, may 
be reduced to Lime. 
Fcrrugineous or metallic petrifying Waters moftly 
a& by infmuating their fineft Particles thro* the Pores 
and VefTels of the Wood, or other Vegetables, with- 
out increafing their Bulk, or altering their Texture, 
tho' they greatly increafe their fpecific Gravity : And 
fuch is the petrified Wood found in or on the Shores 
of Lough-Neagh $ for it doth not fhew any outward 
Addition or Coalition of forcing Matter flicking to 
or covering it (except in ibme Places, where a thin 
(limy Subftance, taken notice of hereafter, is fome- 
times obferved), but preferve the Grain and Vejtigia 
of Wood 5 all the Alteration is in the Weight and 
Clofenefs, by the mineral Particles pervading and fill- 
ing the Pores of the Wood : Thefe Stones, or father 
Wood-Stones, do not make the leaft EfFervefcence 
with Spirit or Oil of Vitriol, nor Aqua-fortis 5 which 
fhews, that they are impregnated with metalline Par- 
ticles, or ftony ones, different from the calcarious 
Kind; and may be the Reafon why the petrified Wood, 
mentioned by N. Grew ( a ), made no Ebullition, at 
which it feems he was furprifed (b). Thefe Stones I 
could not reduce inro Lime by the moft intenfe Fire, 
.nor. 
(a) Reg. Soc- Muf. p. 270. 
\b) This con:radi£ts an Obfervation of Mr. John Beaumont [Phil. 
Tranf. N°. 129. p. 731.), That moftly mineral Stones will 
ftir with Acids ; whereas all thpfe that l have tried, whether Englijb 
or did not at all ftir with Acids. 
