F. A. Ferret — Some Kilauean Fjectamenta. 



613 



bombs of lava which was liquid at the moment of expulsion. 

 Some of the latter are homogeneously solid ; others have a 

 nucleus of more vesicular lava covered with a compact shell, 

 while all show a lesser tendency to form tail-like extensions at 

 the extremities than those of Etna and Vesuvius. This is 

 explained by the lesser viscosity of the Hawaiian lava permit- 

 ting of a spherical adjustment during trajectory which, how- 

 ever, is generally modified by the revolution of the mass and 

 results in a figure which is nearly elliptical (fig. 3). This 



Fig. 



Fig. 3. Elliptical bomb from Kilauea. 



bomb has a length of 10 cm and weighs 660 grams, the nucleus 

 being somewhat scoriaceous with an exceedingly compact shell 

 of l cm in depth. 



A very small, compact bomb found by the writer compares 

 with the similar ones from the 1909 eruption at Teneriffe and 

 from Vesuvius and Etna, as follows : 



Wt. Sp. Gr. 



Kilauea 25-51 g. 2*89 



Teneriffe 25*52 <• 2-92 



Vesuvius 13-50 " 2'50 



Etna 16-61 " 2-15 



