MODE V. GRANITE 189 



bubbly, which on the rod of sappare gains in 

 transparence and sinks, but without penetrating 

 or dissolving, and even without entirely losing 

 its bubbles. 



" This pala'iopetre contains veins of from one 

 to three lines in breadth, which cross at different 

 angles, and small nests of a deep leek-green horn- 

 blende, confusedly crystallised, or in plates rarely 

 straight, or in middling large fibres." 



STRUCTURE I. OF A LARGE GRAIN. 



Aspect 1. Felspar, quartz, and siderite, often 

 joined with mica. 



Red granite of Egypt, from the quarries visited 

 by many travellers beyond Syene, whence it is 

 called Syenites, by Pliny, who specially mentions Syenites, 

 that the obelisks are composed of it ; while it is 

 universally admitted that they are a mere and ge- 

 nuine granite, often containing no siderite *. 



* Both Agricola and Aldrovandi mention syenite: the latter 

 says, Fulgus qppellat hoc genus marmoris granitum rubrum cum 

 antea dieeretur pyrrhopoikilon ; the latter word being also used by 

 Pliny to denote the fiery red variegation of the felspar. 



The celebrated Zoega also informs us positively that all the obe- 

 lisks are of the ancient Syenite, that is, as he adds, our red granite. 

 " Verum enimvero omnes obelisci in Europae civitatibus obvii, 

 ubi excipias unum Florentinum (e granite fusco), et maxima quo- 

 que pars eorum qui in /Egypto exstant, atque in Abyssinia ; faeti 



