56 TRAVELS THROUGH 



marble, and other pre-exifting ftones, are likewiffe 

 found in thefe argillaceous beds j but what evi- 

 dence is there for fuch fubterraneous jafper and 

 agate veins ? And for what reafon are the Vicen- 

 tine hyacinths, cryfolites, and pietre obfidiane, 

 bsing true natural vitrifications, never found 

 with the horn-done flints in the china-clay, but 

 conftandy in the harder lavas ? All thefe circiim- 

 ftances agree in fupport of Mr. Arduini's afiertion, 

 that the before-mentioned flint horn-ftones, found 

 among volcanic materials, are owing to fubterra- 

 neous fire and its meltings. Knowing, that by 

 vitrefcent compofitions and chemical fire even the 

 ftardeft precious ftones can nearly be imitated, 

 why mould we deny the fame power to Nature 

 and its greater fubterraneous furnaces * ? I do not 



* To prevent miftakes, and the charge of inconfequent wri- 

 ting or reafoning, the Author fhould have explained himfelf 

 Tvith i more propriety, and with more juftice to nature, and per- 

 haps to Mr. Ardulni. Therefore the Tranflator, who has ex- 

 amined feveral vclcanos, and fkidied Nature in her own manu- 

 factories or officines, endeavours to let him right. His obfer- 

 yations are fo far agreeing with Mr. Forty's and Arduinis^ that 

 he confiders the chalcedonies as volcanic productions, but in 

 n quite different fenfe, as that, in which the afhes and lavas, 

 with their various inclofed Iherl-cryftallizations, chryfolite, or 

 hyacinth-like vitrifications, and pietre obfidiane, are called fo. 

 Thefe are undoubtedly immediate productions of the fire and 

 violent melting; the former being \>\\t paraftical Jlones of ' <vo!~ 



