HAWAII. 225 



Dr. Pickering found a new route of descent into the crater, and one 

 that he deemed the most easily accomplished. This was on the south- 

 east side, near the sulphur-bank. 



While in the crater on the black ledge at night, there is often a 

 deceptive appearance of a rising storm, from the darkness produced by 

 the overhanging cloud. 



The old crevices have been found to be the only ones that give out 

 steam. 



Though volcanic action is and has been so rife in this group of 

 islands, and so many appearances of it are to be seen on the surface, 

 both in the crater shape, and also that of lava crevices and jets, yet 

 there are but few that ou°[ht to claim the name of volcanoes. Those 

 that attract most attention are Mauna Loa, Kilauea, and Hualalai, as 

 being in present action, and the great crater of Haleakala. These 

 have already been described sufficiently in the foregoing pages. 



Cone-craters, or hills of scoriaceous lava, are found throughout the 

 group, sometimes on the sides of the larger mountains, at others 

 isolated near the coast. Many of these are composed of fragments of 

 lava and sand. They are likewise to be seen in the terminal craters 

 of Mauna Loa and Haleakala, and do not appear to have ever dis- 

 charged any fluid lava, but seem to owe their shape to the successive 

 discharges of the loose materials. They are frequently in a lineal 

 direction, as will be observed by inspecting the map of Hawaii ; but 

 this will give little idea of their number. If reports be true relative to 

 Hualalai, hundreds may be seen from its summit, like excrescences on 

 its sides. 



One of the most striking features of this island is the difference in the 

 formation of the two great mountains, whose height so nearly corre- 

 sponds. The form of Mauna Loa is unique, and has been increasing, 

 from the overflow of its terminal or pit-crater, and may perhaps be 

 entirely formed by the boiling over of this, for upon reflection this 

 would not seem impossible, but, indeed, quite probable ; and one is irre- 

 sistibly drawn to this conclusion on ascending it. 



The extent of the lava stream flowing over the surface is very great, 

 and has been supplied by most copious springs ; the recent flow, for 

 instance, covered an area of twenty square miles with a thickness of 

 twelve feet on an average. The height of Mauna Kea has been in- 

 creasing from the effects of the cone-craters, of which there are now 

 nine on the surface of its flat top : thus while one gives out a molten 

 mass, the other sends forth scoria. 



The pit-craters are also represented on the map. They have not 

 been the seat of volcanic action, yet from their extraordinary forma- 



vol. iv. 29 





