.DOMAIN 2. 



while Gioeni and other writers on volcanoes 

 say, that very seldom a piece without pores can 

 be found, even of a few inches in diameter. A 

 specimen of compact lava in the British Museum 

 contains melted garnets ; and is of such an ap- 

 pearance that no eye can confound it with basalt, 

 even of the finest texture: yetFaujas, and other 

 late French writers, persist in restricting the 

 term basalt to a supposed lava, while they use 

 the term trap for the real basalt of the ancients ; 

 which, even by their own volcanic theory, is of 

 quite a different nature and origin*. 



In his description of the Borgian monuments,. 

 as already mentioned, Wad found that those of 

 basalt might chiefly be referred to siderite or 

 hornblende : and it is remarkable that the word 

 basaltes, according to Pliny, signified iron in the 

 Ethiopic language, as sideros does in the Greek. 

 The basalts of the ancients are often siderites, 

 sometimes with veins or grains of felspar or 

 quartz ; sometimes with olivine : the only an- 

 tique specimen in which leucite occurs having, 

 as Wad observes, been sculptured at Rome. 



Some small Egyptian monuments, however, 

 occur j n ji ne basalt, here called basaltin : to 



* The name lasalt seems subject to a singular fatality of abuse, 

 the grave Wallerius having, with equal skill, degraded it to com- 

 mon schorl ' 



