J. D. Dana — History of the Changes in Kilauea. 85 



only increased in size, but it had actually risen in height as 

 much as it had been previously depressed by the out-draining 

 of lavas in the. eruption of 1840. This gradual rising of the 

 solid embankment of the lake cotemporaneously with the lake 

 itself, together with the filling up of the whole interior of the 

 crater, is doubtless to be attributed to the combined effect of 

 repeated overflowing together with the upheaving agency of 

 subterranean forces." 



Mr. Lyman took a few compass bearings in the crater, and 

 some angles with a quadrant which he had constructed for the 

 Kilauea visit, and left, with a friend on the Islands, a rapidly 

 penned sketch of the crater showing the general condition of 

 the interior. A reduced copy of the map with its lettering is 

 here given. The chief discrepancy between it and the descrip- 

 tion is in the large interval between the " ridge " and the 

 "canal," the latter beingtoo near the outer wall. The " ridge," 

 as. is seen, is made to extend through half the circumference of 

 the lower pit. The " Furnace," marked on the map, is described 

 in his paper as oven-like, ten or twelve feet high, with walls a 

 foot thick ; as being inactive but showing within a glowing 

 white heat early in July, but "in full blast" at his second visit 

 in August, six weeks later. The large depression in the crater, 

 which contained steaming fissures and chasms, appeared to 

 have been the site of a former lava-lake. 



