( 3 ) 



Etna^^Large pieces of red porphyry which 

 do not fee fn to have fuffered fifion — None 

 ofthefe bodies difpofed in currents ; "whence 

 it is probable that they have been throivn 

 into the air by fome volcano — A fpaciouS 

 plain of tufa rendered cultivable^ fituatcd 

 beyotid the Monte della Stufe, ivhich 

 affords numerous pieces of the fneji and 

 purejl glafs found in Lipari — Local ori^ 

 gin of this glafs — Bed of pumices on 

 the ebctejffve current of tufa before men- 

 tioned — Stoves of Lipari defcribed — Re- 

 mains of confagrations of fulphur under" 

 them^ and in their envirojis — Prodigious 

 number of lavas decompofed by the a£iion 

 of fulphur eons acid vapours — Oxyde of 

 pure iron depoftted on fome of thefe lavas 

 '—Variety of colours which they preferit to 

 the eye — Their decompofition ufually in the 

 inverfe proportion of the depth of their 

 majfes — Widen freed from the decompoft" 

 tion which renders it difficult to afcertain 

 their nature^ they are ufually found of a 

 petrofiliceous bafe — This decompoftion an 

 ohjlacle to their fufton in the Jurnace-^^ 

 B 3 Expli* 



