436 DOMAIN XII. VOLCANIC. 



products, which had at first been supposed to be 

 simple. 



" But to render complete my enquiries rela- 

 tive to the pumices of Campo Bianco, it was 

 necessary that I should not confine my re- 

 searches merely to the part of the mountain I 

 have mentioned, but extend them to all the 

 principal places where they might be found. 

 This I did, accompanied by two natives of 

 Lipari, whose assistance was particularly useful 

 to me, as they lived by digging pumice, and 

 were well acquainted with every part of the 

 mountain, and the different kinds of pumices it 

 contained. It is impossible to describe the dif- 

 ficulties I met with in these excursions. We 

 frequently passed along the edges of the deep 

 ditches made by the rain-water, at the hazard, 

 in case of a false step, of falling into them, and 

 not easily getting out again ; or the still greater 

 danger of precipitating into the sea. The daz- 

 zling whiteness of the pumice, equal to that of 

 snow, increased my fears; for I made my ex- 

 cursions in the day time, when the sun shone, 

 and was strongly reflected by these stones. 

 Every one knows that snow, besides dazzling 

 the sight, is accompanied with the inconve- 

 nience, when it is deep and has lately fallen, 



