62 Dr. Beddoes’s Obfervations on the 
may we not expedt to find them incorporated together, and in 
every ftate of diffufion and reparation ? 
Under this head I (hall only remark further, that feveral 
late obfervations, from which it has been inferred, that certain 
extindl volcanos have been feated in the heart of granite *, feem 
to admit of a much more eafy explanation, on the fuppofition 
that granite has cryftallized from fufion. f. Volcanic fires 
reach to a much greater depth than any at which we have had 
an opportunity of making obfervations. The focus in different 
inftances may be feated at a different diftance from the furface ; 
but none are probably lefs than feveral miles at leaft deep. 2. 
The currents of granitic lava -f in the Pontian ifles leave little 
room to doubt of the power of fubterraneous fire to produce 
this fubftance. To fuppofe them to be rocks of granite fufed, 
but otherwife unchanged, and that even fiffile rocks may be 
made to flow without lofing their laminated ftrudture; is as bold 
an aflumption as can eafily be taken up. In the great igneous 
procefles of nature fire need not be imagined to a£t otherwife J 
* Dolomieu, Ifles Ponces, p. 30, 31. and Ifles de Lipari, in various parts. 
-f- Dolomieu, /. c. paffim , and particularly p. 89 — 97. Inflru&ive as the 
particular fa<ts defcribed by this excellent mineralogifl always are, I rauft diflent 
from him both on the mode of a&ion of volcanic fires, and on the production of 
zeolite and other cryflals, in glandular rocks, for the reafons afligned here and 
below. 
J t£ Le feu produit, dans les laves, une fluidite qui n’a aucun rapport avec la 
fiuidite vitreufe que nous operons Celui des volcans n’a point d’inten- 
fite ; il ne peut pas meme vitrifier les fubflances les plus fufibles . . . . il pro- 
duit la fluidite par une efpece de diffolution, par une fimple dilatation qui permet 
aux parties de glifier les unes fur les autres (Dolomieu, Avant-propos, p. 8.). 
See alfo p. 84. Fire in a crucible produces fluidity no otherwife ; and when 
there is this freedom of motion among the partieles , how can we fuppofe the 
cryflals of granite and the leaves of fchiftus to remain unmixed even in a current 
of lava? 
than 
