BETWEEN 1855 AND 1868.
In March and October, 1856, there was some sluggish lava in Halemaumau and hundreds of steam jets. The inner platform of hardened lavas keeps its elevation of about six hundred feet above its level of 1840.
J. H. Wood in 1892 says that in 1856 the crater floor was sev rael hundred feet deeper than at the time of writing. There were cones, chimneys and blow holes, and a ridge of rocks entirely gone later. The caldron was surrounded by a rim thirty feet above the crater floor and fifty feet above the lake, where the lava was surging, spouting and tossing masses from minute particles to tons in weight.
In June, 1857, Halemaumau was a lake of five hundred feet diameter surrounded by ragged walls a hundred feet high. Every three minutes a crust would form and then be broken up.
There was little change in the conditions during 1858. In August the great lake had the same size as in 1857 and there was a constant freezing of a crust alternating with fractures and melt ing.
In 1859 Kilauea was comparatively quiet, showing no sympathy with the great outpouring upon Mauna Loa. For several years about the same story of the comparative quiet of the central lake, the constancy of the lower platform and occasional small displays of fire is told.
Halemaumau was a lake about six hundred feet in diameter. Without it, in the basin, there was a driblet mound with pin nacles and turrets. In 1863 a large fountain played at the mid dle of the lake at intervals from a few seconds to half a minute, throwing up crusts of lava ten or twelve feet high, and smaller portions twenty or thirty feet high. Elsewhere it was covered by a thin crust easily ruptured by small stones thrown upon it. In October, 1863, the great lake and the black ledge were covered by fresh lavas, while the central table land five or six hundred feet above the floor of 1840 showed no change.
In 1864 Mr. W. T. Brigham commenced his examination of the volcano and its surrounding. With instruments he made an accurate map which has been the basis of every plan published since that time. This is reproduced, as modified by Captain Dut ton, in Plate 31; and from it one can learn the conditions preva lent in 1864 and 1865 and note the changes from the features de scribed by his predecessors. Professor Dana comments freely
upon these data in his book.
Some of the dimensions as measured upon this map are as fol lows : The main caldera is nearly three miles long; the greatest width nearly two and one-quarter miles; extreme length of the depression from north of the sulphur bank to extreme south end three and three-quarter miles ; upper triangular platform near the house nearly one mile long; circumference of the main pit eight and one-half miles. The bottom of the pit is stated to be "more than four hundred feet." The observations relate to 1864, i865, and the map surveys were made in 1865, between August 20 and 24.
The following features are distinctive : The floor is essentially upon the same level, the lower pit having been nearly obliterated by the lava overflows. The position of the margin of the black ledge is indicated by the "high rock" and "ancient lava," obvi ously identical with Lyman's ridge of loose blocks ; by the two small lava lakes near the northwest corner, two patches of lava farther south and the active cones, one on each side of the pit. A painting by Mr. Perry in i865, as photographed by Brigham, shows the position of the black ledge very plainly, in the slight shading; but the whole bottom was regarded as the black ledge. The sulphur banks on the southeast side of the pit are smaller than ever before. Halemaumau has its old position, and had a diameter of eight hundred feet in 1864 and i,000 in August, 1865. It was surrounded by walls fifty feet high in 1864 and thirty feet high in 1865. Judging from the illustrations the surface of the molten lava was considerably agitated. Occasionally the liquid rose suddenly several feet and was "boiling violently and dash ing against the sides, throwing the red-hot spray high over the banks." "There was no noise except the dash and sullen roar." The two small islands present in 1864 had disappeared in 1865.