318 DOMAIN XII. VOLCANIC. 



surface; while considerable labour and time 

 must be employed to arrive at the true compact 

 lava*. 



It must also be remembered that Ferber regards 

 basaltin as a volcanic production, in which he is 

 followed by almost every writer, German or 

 French, who has visited volcanic countries. As 

 it is Werner's plan never to decide on substances 

 or regions, which he has not seen with his own 

 eyes, it is much to be regretted that he did not 

 visit Vesuvius, if he could not attain the majestic 

 scenes of Etna. 



While the French writers are often so preju- 

 diced in favour of volcanoes, that with them every 

 black or vesicular stone is a lava; and the Ger- 

 mans, on the other hand, deny even obsidian and 

 pumice to be volcanic ; both sides injuring their 

 own cause by pushing it to an absurd excess ; it 

 inay be satisfactory to know the ideas of Ferber, 

 Viho is at least regarded as an unprejudiced writer. 

 Besides the black homogenous lava, above men- 

 tioned, his other compact sorts are black with 

 leucites, with felspar, with siderite, with chryso- 

 lite, with vesuvian, with obsidian. He adds four 



* Saussure, i. 128, 4to. has observed, that compact lava is very 

 rare, and found only in the interior of the current. So also Ferrara, 

 p. 301, "la parte bassa dei torrenti fe fornaata di lava piu o meno 

 eompatta." 



