MODE III. BASALTIN. 53 



poses ; its weight is about twice and a half 

 greater than that of water ; it melts easily under 

 the blowpipe into white amel*, and seems to be 

 composed of the same elements as felspar, but 

 confusedly united ; it contains a great quantity 

 of crystals of felspar, some acicular crystals of 

 hornblende, and even some spangles of mica. 

 The klingstein-porphyr of the Germans f, which 

 is found in considerable quantity at Mont Dor 

 and Cantal, seems s to be only a remarkable va- 

 riety. 



" These porphyroid masses so nearly resemble 

 certain productions in the humid way, that it 

 required nothing less than their extraordinary 

 position, their situation in the midst of volcanoes, 

 some unequivocal marks of the action of fire, 

 their passage direct or indirect to basalt, and 

 above all the volcanic scoriae imbedded in their 

 mass, to prove that they are foreign and poste- 

 rior to the productions in the humid way, and 

 that they owe their existence to the volcanoes. 



" Nothing positive can be said as to the man- 

 ner in which they have been produced, and 

 arrived at their present position. No where is 



* See Johnson. Enamel is properly the application of the amel 

 to another substance. 



f Klaproth procured 8 per cent, of soda from caat of Bohemia, 

 and Mr. Bergman 6 from that of Mont Dor. 



