J. D. Dana — History of the Changes in Kilauea. 283 



tions were made to its outside by ejections. It continued to rise 

 bodily until it was as high as the near walls of Kilauea (xxxiv, 

 86). Between 1880 and 1 882, another debris cone began in the 

 basin of Halema'uma'u which, as he describes, rose in like man- 

 ner without additions to its summit, and finally became 200 

 feet or more high ; this cone continued to exist until the erup- 

 tion of 1886. 



The subterranean force appealed to was plainly force arising 

 in some way from the lavas beneath. Mr. Coan, in his letters 

 to me, supposed that the lifting was produced by the injection 

 of the lavas of the conduit into open spaces between the solid 

 layers below. 



(4) Again, in the summer of 1886, three months after the 

 eruption of that year, the debris from the falling walls of Hale- 

 ma'uma'u were seen to be made into a cone occupying a large 

 part of the interior of the basin ; and from August onward, it 

 was apparent that the cone so made was slowly rising, though 

 having little outside additions ; in October, its top was on a 

 level with the rim of the basin ; in January, 200 feet higher, 

 so as nearly to overtop the southeastern Kilauea walls. It was 

 early apparent to visitors at the crater that the elevation was 

 through action below ; and soon the conclusion was general, 

 among observers, that the cone, as expressed in the words of 

 Mr. Dodge, of January 14, 1887, was " rising slowly as though 

 floating on the surface of the new lava-lake.* The mean rate 

 of elevation, according to the heights given, was about two feet 

 a clay.f 



The ascensive force was thus proved to be great, and its 

 effects to. have fundamental significance. 



2. Method of Action.- — It is a question whether, in the lift of 

 the floor of the great crater in 1823, 1832, 1840, 1868, the lavas 

 of the lava-conduit acted by direct thrust, or through injections 

 into spaces between the layers of solidified lava beneath \i.\ 

 The facts favor strongly the former of these views. In the 

 first place, the lateral .thrust in the upper lavas of a conduit is 

 necessarily feeble ; for the conduit there, or near by, opens to 

 the surface. Then secondly, it is quite certain that the breadth 

 of the Kilauea conduit at top has been, at the times of these up- 



* This Journal, xxxiv, 70. 



f I was informed, when at Honolulu, by Mr. Parmelee, of that place, that in 

 August of 1886, he made observations on the rate of change of level, by sighting 

 from the Volcano House verandah over a post 100 yards in front of the house, 

 and marking the change of the line of sight on a pillar of the verandah. His ob- 

 servations were made between the 19th and 21st of the month, on the first 

 day of the rise, according to his calculated result, was 16 feet ; on the second, 17 ; 

 and on the third 8 feet. These numbers are large. They were -not verified by 

 observations near the cone. They at least prove progress in the elevation. 



% The latter is the explanation adopted by Mr. Brigham in his paper of July, 

 1887, xxxiv, 19. 



