410 "W. T. BRIGHAM ON THE VOLCANIC PHENOMENA 



wonderful than the action of slender cones as described by Mr. Stewart. Where the subter- 

 ranean discharge which emptied the crater, reached the sea, is not known. 



Mr. David Douglass was at Kilauea in January 1834, and measured the depth 



of the pit at one thousand feet. A lake of boiling lava at the north end was three 

 hundred and nineteen yards in diameter. The Halemanmau was much in the condition as 

 described by Mr. Ellis. 1 



On the 8th of May 1838, Captains Chase and Parker visited Kilauea, and their 



description has been published with a sketch of the crater. 2 The lavas had again 

 nearly reached the black ledge, and all over a surface of four square miles were cones and 

 lakes of fire ; twenty-six of the former were counted, eight of which were ejecting cinders 

 and red-hot lava. Six small lakes were boiling violently, becoming crusted over, cracking, 

 and again boiling. On the Halema\imau was an island which the lava was not seen to 

 overflow. The remarkable oscillations in the heat, remarked by all visitors, seem to have 

 taken place on this occasion with more than the usual rapidity. As they were looking at 

 one of the lakes which was boiling violently, they say: "After a few minutes, the violent 

 struo-srle ceased, and the whole surface of the lake was changed to a black mass of scoria? ; 



OO * CD 7 



but the pause was only to renew its exertions ; for, while they were gazing at the change, 

 suddenly the entire crust which had been formed, commenced cracking, and the burning 

 lava soon rolled across the lake, heaving the coating on its surface like cakes of ice upon 

 the ocean surge." As they left the crater, nearly a quarter of the floor gave way, forming a 

 vast pool of liquid lava. 



Count Strzelecki, in the same year, estimates the size of five of the lakes at about five 

 thousand seven hundred square yards, and they were almost at the level of the great area. 

 The Halemdumau was encircled by a wall of scoriae fifty yards high, and covered an area 

 of three hundred thousand square yards. 3 



Captain John Shepherd was at the crater September 16th, 1839. The Halema'u- 

 mau was estimated at a mile in length and half a mile in breadth, and flowed over 

 in some places " leaving ridges of scoria? on the northern side." 4 



It took nine years for Kilauea to fill up after the eruption of 1823 ; and for eight years 

 the process had been continued until the lava had reached a point nearly a hundred feet 

 above the black ledge which seems to be about the limit of pressure the walls of the moun- 

 tain will bear. The force tending to rupture the mountain may be readily calculated, 

 assuming the pressure of every twelve feet of lava to be fifteen pounds to the square inch- 

 and as the crater is usually emptied to a depth of four hundred feet we have a pressure of 

 five hundred pounds to the square inch. It must be remembered that the mountain wall is 

 by no means solid and compact, and although successive discharges may strengthen some 

 volcanic mountains, here the effect seems to be quite the contrary, owing to the extreme 

 fluidity of the lava which runs off, leaving tunnels and caverns instead of solid interlacing 

 dykes ; consequently the discharges usually follow the same direction. 



Kilauea, then, was ready to break out, and in 1840 the most extensive eruption recorded 

 took place. 



Rev. Titus Coan thus describes the eruption of 1840 in a letter dated September 

 1840 ' 25th, 1840. 



1 Journal of the Royal Geographical Society, vol. iv. 3 Hawaiian Spectator, vol. i., p. 435. 



2 SiUiman's Journal, [n. 8.] vol. xl., p. 117. 4 Athenmum, November 14, 1840. 



