k 



I 



1 



k 



THE SANDWICH ISLANDS. 



135 



lysis of Pele's Hair (No. 20), in which both potash and soda Ukpeb 

 are given — H. W . Bristow. Gallery. 



20. Capillary lava, or volcanic glass, lava when 



in a very fluid state blown by the wind into hair-like fibres. 



It is called by the 



P< 



the principal 



goddess of the volcano. In chemical composition it closely 

 resembles augite. The following analysis is given by 

 Dana :— -Silica, 39-74 ; alumina, 10*55 ; protoxide of iron, 

 22-29 ; lime, 2-74 ; magnesia, 2-40; soda, 21-62. 

 Kilauea, Island of Hawaii. 



Dana describes the mode of formation of this substance 



from actual observation, as follows 



" It covered thickly 



the surface to leeward, and lay like mown grass, its threads 



lava) 



(of melted 

 On watching the operation a moment, it was appa- 



rent that it proceeded from the jets of liquid lava thrown 

 up by the process of boiling. The currents of air, blowing 

 across these jets, bore off small points, and drew out a 

 glassy fibre, such as is produced in the common mode of 

 working glass. The delicate fibre floated on till the heavier 

 end brought it down, and then the wind carried over 

 the lighter capillary extremity. Each fibre was usually 

 ballasted with the small knob which was borne off from 

 the lava-jet by the winds."— (" Geology of the United 

 States' Exploring Expedition," 1828-42, p. 179.) 



2 1 — Vesicular scoriaceous lava, 



shewing 



on one 



side a smooth surface on which the melted lava flowed. 



22. — Very vesicular scoriaceous lava. 

 23. — Vesicular scoriaceous lava from the outer por- 

 tion of the stream. — Kilauea. 



24. — Finely vesicular reddish brown scoriaceous lava. 

 25 & 26. — Very vesicular lava. 



27. Scoriaceous lava, or volcanic slag ; very 

 cular. 



28 — Cellular basaltic lava, Hawaii. 



vest- 



29. 



Wall-case 1» 



VOLCANIC 



