<52 EXPERIMENTS on ll'IIINST'ONE and L/IVJ. 



■which fuiTound Mount iEtna. The fituation of this mafs is 

 fingular : It reils upon a Httle hill, formed of loofe fcoria, the 

 funimit and fides of which are covered by the (tony mafs, fb 

 that no crater is vifible. It flruck me on feeing it, and I found 

 M. Doi-OMIEU had formed the fame opinion, that the lava had 

 rifen up in a perpendicular diredlion, and had flowed over on 

 all fides. Its great thicknefs, and fmall extent, feem to favour 

 a conjecflure which this naturalifl has formed with regard to 

 Jeveral lavas, that they were erupted at the bottom of an ocean 

 which once covered Sicily, and, being quickly cooled by the 

 conta«5l of water, had been prevented from flowing far. The 

 conjedture feems plaufible enough * ; and, having no proof that 

 this fubftance made part of an external current, as I have with 

 refpecfi: to the firll two mentioned, I do not exhibit it as a lava 

 with the fame confiden<;e. Whatever be its hiftory, however, 

 it poflefTes the chemical properties common to whin and lavas. 

 Its glafs yielded a dark grey cry! tallite of uniform texture. 

 Befide it in the drawer, now on the table, I have placed a cry- 

 flallite, formed from the whin No. i. which refembles it in 

 every relped. 



No. 4. Lava of Iceland. 



I RECEIVED the fpecimen from a perfon who found it on the 

 fpot ; but not being acquainted with the circumftances of its 

 original pofition, I cannot be certain that it is a lava. It has 

 however every appearance of being fuch. 



It is a blue homogeneous fubftance, having fome chryfolites 

 fcatter.ed irregularly through it. Nearly half its bulk is occu- 

 pied 



* JI. DoLOMiEU afcribes the formation of part of Mount Mxns. itfirlf to a fitnilar 

 caufe. I fliall have Occafion, in another part of this paper, to confider that opi- 

 nion. 



