524 



ASCEXS/OX 



explanation. The intcrN-ening- spaces arc concealctl with layers 

 of pumice, ashes, and volcanic tuff. \Miil>t passing;- this end of 

 the islaoLl at sea, I could not imagine what the \\'hite patches 

 c with which the whole plain was mottled ; I now funid 

 t the\- were sea -fowl, sleeping in such full confidence, that 



weiu wiiu Hiiicu Lue wnoie piam was mcHticu ; i now n 

 that the}- were sea -fowl, sleeping in such full confidence, .....^ 



even in mid-da\- a man could walk up and seize hold of them. 

 Thes- '-^--'^ - ' ------'-■ ■ - T 



whol 



light, came tumbling o\'er the broken lax'a rocks. 



The geology of this island is in many respects interesting. 



n in mid-da_\- a man could walk up and seize hold of them. 

 esc birds \\cre the only li\-ing creatures I saw during the 

 :>\e da\-. On the beach a great surf, although the breeze was 



it. came tliniblin'T o\-i^r thp hrnt-rn ].i\-^ rnrl-s 



CFLLl'LAR FOR]\IAT10N OF VOLCAN'IC BOMB 



In several places I noticed \-olcanic bombs, that is, masses of 

 lava which ha\e been shot through the air whilst fluid, and ha\-c 

 consequentl}- assumed a spherical or pear-shape. Not only 

 their external form, but, in several cases, their internal structure 

 shows in a \-cry curious manner that they ha\'e revolved in their 

 aerial course. The internal structure of one of these bombs, 

 when broken, is represented \-ery accurateh- in the accompan\"ing" 

 woodcut. The central part is coarsely cellular, the cells 

 decreasing in size towards the exterior ; ^\■hcre there is a shell- 

 like case about the third of an inch in thickness, of compact 

 stone, which again is overlaid b_\" the outside crust of finely 

 cellular kwa. I think there can be little i.loubt, first, that the 

 external crust cooled rapidl\- in the state in which we now sec it ; 



