NOME V. PUMICE. 



433 



whether the action of the waves might not con- 

 cur to produce the roundness of their figure, I 

 rather chose to make my observations on those 

 that actually formed the beds; which I did, by 

 climbing up one of the sides where the ascent, 

 though difficult, was not impracticable. Here 

 I found pumices approaching, some more some 

 less, to the globular form ; and of different sizes, Globular, 

 some not being larger than nuts, and others a 

 foot or more in diameter, with innumerable sizes 

 between these extremes. Though the ground 

 colour of them all is white, in some it inclines 

 to yellow, and in others to grey. They swim in 

 water, do not give sparks with steel, nor cause 

 the least motion in the magnetic needle. Their 

 fracture is dry and rough to the touch ; their 

 angles and thinner parts are slightly transparent 5 

 and their texture in all of them, when viewed 

 through the lens, appears vitreous; but this 

 texture has diversities, which it will be proper to 

 specify. 



" Some of these pumices are so compact that Compact, 

 the smallest pore is not visible to the eye ; nor 

 do they exhibit the least trace of a filamentous 

 nature. When viewed through a lens with a 

 strong light, they appear an irregular accumu- 

 lation of small flakes of ice ; their compactness, 



VOL. II. 2 F 



