288 J. I). Dana — History of the Changes in JCilauea. 



Yolcano House, and " to all appearances, the lavas will soon 

 be running into New Lake." 



The description given by Professor Yan Slyke of the cone as 

 seen by him in July, 1886, gives particulars as to the steam- 

 holes in and beneath the cone, and the blowing-cone work, 

 which began this work of destruction and prepared the way 

 for the subdivision. He states that he ascended the cone to a 

 perpendicular well, which opened through its side by a bole 

 " 30 or 40 feet wide and 60 to 75 feet long," and looking down 

 to the bottom 100 feet below, saw the lavas rising and falling 

 in jets from a small vent. In another well of like depth, 20 

 to 30 feet in diameter, there was a cone and " lava boiling with 

 intense violence" (xxxiii, 96). 



This destructive work brings the cone to its end either be- 

 fore, or during, a period of eruption ; and a floating island 

 may be the last phase before its disappearance. 



(4.) Opening of new lava lakes. — With the intensifying of 

 the fires of the crater there has often been, as the history 

 shows, an opening of lakes over the interior o^ the crater, and 

 especially along the borders of Kilauea, or the region of the 

 black ledge. Such facts signify, as I have explained, that the 

 broad underlying conduit of Kilauea, which is like a great 

 reservoir of lavas beneath the pit, reaches at such a time up to 

 the surface, not only in the Halema'uma'u basin through the 

 great conduit, but also in minor lakes through secondary con- 

 duits. It is a query whether this has ever been brought about 

 by new sources of vapor starting in the underlying reservoir, 

 as a consequence of subterranean conditions ; whether hot 

 vapors from such a source have not forced a way through to 

 the surface in consequence of their own dissolving and fusing 

 heat and that of the lavas, and thus have made a new lake ; — as 

 ascending air from the bottom of an ice-covered pond makes a 

 hole through the covering of ice. But such lakes, as remarked 

 on a preceding page, are generally begun over fissures, and it 

 may be that fissures, under the general increased activity, are 

 all that are needed for the result. 



(5.) Extending the limits of the conduit by fusion. — An- 

 other suggestion comes from the fusing power of the Halema'u- 

 ma'u lavas. If these lavas can slowly, even at their surface, 

 fuse stoney lavas, what is the extent of the fusing power at 

 depths below where there is greater heat ? An increase in the 

 heat from a subterranean cause would necessarily widen the 

 limits of the conduit. It is a question whether an extended 

 subterranean bed of liquid lava, thick enough to remain per- 

 manently liquid in spite of cooling agencies about it, can 

 occupy its place without fusing and incorporating with itself 

 any solid lavas directly underneath it, if such there be ? A 



