Bafalt. 443 ftill more extraordinary to find, that fliorl, (6 fufible a fubftance, has not received the fmall- “ eft alrcration, has preferved its angles, its “ hardnefs, its internal texture, and, in general, “ all its Properties. How has it happened that “ th's ' ngk obfervation has not indicated that “ the fufion of lavas has no relatira to the vi- “ 'rcous fufions Which vve operate in our fur- “ naces > l cannot, tncrefore, too often repeat, « that the ßuidity of lavas is not a vitnhcation ; « thev flow, becaufe they are carnpd off l»y a ,e fubftance extremelv fufible, which burns at « the fame time ; and when they congeal, it is « lefs through the ceflation of heat tiun on ac- « count of the entire combuöion and diffipation « of the matter that operated thtir lottnels. Tr is furnrizing he has not narfteu bitumen, left them porous, alfo fotcened fhorls anu zco- lvtes and rendered them porous ? . . I fh^Ü now proceed to lh=« d>c mfufency of the Principal volcanic theories of tue formnuon pf bafalt, begmning with Delmaretz.s as l1 firft, and ftill the moft generaiiy recei‘ ; ineenious academician iuppofes thht balalts v\ere Sy the coolsng of Im erupted from an- i LnLns • if lüf we fliould naturally expect tlCI f; ^ them in the currents of modern volcanos; t° hnd them m the ci Uton 3llo;vs this, SSfÄ« proof oi •*«*** own hypothefis; Mr. Dolomieu aflures us, that, of che modern mrrents of lava from üitna^many have been Oawed by cooling in the open air, )*t they prefent nothing but irregulär mafios ; nuny alfo of the more anuent beus ot lava have ocu