CAPTAIN DUTTON'S VISIT IN 1882.
A very complete and satisfactory account of Kilauea is that given by Captain Clarence E. Dutton in the Fourth Annual Re port of the United States Geological Survey and the attempt will be made to present its most important points. He applies to the volcano with some hesitation the term which is equally appropriate for Mokuaweoweo, Haleakala and other Hawaiian ex amples. It is what Wilkes, and after him Dana, calls a pit crater. Geikie uses caldera to signify explosion-craters and crater lakes, citing as examples Palma in the Canary Islands, Val del Bove in Etna, eleven illustrations in Ecuador, the crater " On ref errng to Lyell's Elements of Geology, 1865, one may learn why the term Caldera began •to be used. Lyell describes the volcano upon the island of Palma called "La Caldera." Within it is a bowl-shaped cavity from three to four miles in diameter, encircled by a precipice from 1,500 to 2,000 feet high. Upon one side a breach has been effected where there is a descent of two thousand feet from the center of the Caldera to the sea. The layers of volcanic rocks dip quaquaversally outwards, usually at a small angle but in some places as much as forty degrees. Von Buch had spoken of this volcano as a cone of elevation. Lyell prefers to apply to it the theory of engulfment and speaks definitely of a Caldera as a type of volcano, to which are also referred the Val del Bove of Etna, and one in Java, p. 621. Lyell therefore preceded Dutton in the use of the term Caldera, but both agreed as to its signifi cance. Early authors have referred these and others to crater rings; such as the Somma about Vesuvius, Bourbon, a circle four miles in dia meter, and Teneriffe. The supposed original Krakatoa belongs to this category.
lake Mazama in Oregon, and others. The origin of Kilauea is not so clearly a case of explosion as in the other cases cited. Dut ton, however, does not enter into the discussion of the origin of the caldera. Plate 34 is a copy of a panorama presented in his report.
Starting from the Volcano House the path leads over a series of steps that have been faulted off from the main platform of the country. On reaching the bottom the way leads over freshly formed pahoehoe, rolling smooth-surfaced bosses, not much in clined, but at about one and three-fourths miles the slope is much steeper for about one hundred feet. Reaching the summit he came to the "New Lake," said to have appeared first in May, 1881, being about four hundred and eighty feet is g and over three hundred wide, surrounded by walls fifteen to twenty feet in height.
"When we first reach it the probabilities are that the surface of the lake is coated over with a black, solidified crust, showing a rim of fire all around the edge. At numerous points at the edge of the crust jets of fire are seen spouting upwards, throwing up a spray of glowing lava drops and emitting a dull simmering sound. The heat far the time being is not intense. Now and then a foun tain breaks out in the middle of the lake and boils freely far a few minutes. It then becomes quiet, but only to renew the opera tion at some other point. Gradually the spurting and fretting at the edges augment. A belch of lava is thrown up here and there to the height of five or six feet and falls back upon the crust. Presently, and near the edge, a cake of the crust cracks off, and one edge of it bending downwards descends beneath the lava, and the whole cake disappears, disclosing a naked surface of liquid fire. Again it coats over and turns black. This opera
tion is repeated edgewise at some other part of the lake. Sud denly a net work of cracks shoots through the entire crust. Piece after piece of it turns its edge downward and sinks with a grand commotion, leaving the whale pool a single expanse of liquid lava. The heat is now insupportable, and for a time it is necessary to withdraw from the immediate brink. Gradually the surface darkens with the formation of a new crust, which grows blacker and blacker until the last ray of incandescence disappears. This alternation of the freezing of the surface of the lake and the break up and sinking of the crust goes on in a continuous round, with an approach to a regular period of about two hours. The interval between the break-ups varies, so far as observed, from forty minutes to two hours and a quarter. Probably the average interval is somewhat less than two hours. The explanation of the phenomenon is not difficult." The following is an abstract of the text : Melted silicates oc clude notable quantities of water and when they solidify they exclude the water just as water itself excludes air in freezing. The excluded gases are mechanically entangled as bubbles which are numerous enough to diminish the density. The first inch or two of crust which forms is cooled quickly and becomes stiff and black in a few minutes and is termed tac/zylite. Being full of vescicles and spongy it is light enough to float. Subsequent ad ditions to its thickness are made to its under surface. These be come more and more compact through the disingagement of the gases, thus increasing the specific gravity. When this has con siderably increased the position is unstable, and rupture once started is quickly propagated through the entire crust, which goes to pieces and sinks.
Less than half a mile northerly is the greater lake or Hale maumau, nearly i,000 feet long, six hundred feet wide, and five hundred and eighty feet below Uwekakuna. It is surrounded by cliffs an hundred feet high with a plenty of talus of irregular blocks. The lava is more active ; the surface is covered with boiling fountains, but they do not spout high. Because of the unquiet surface the crust cannot form as at the New Lake with regularity. There are occasional thin detached sheets which sink from time to time. The outer cone is composed of masses of lava that have been pushed up with much shattering and contor tion. There are cones within cones, more like a crater. That it has been elevated is testified to by those who have occupied the Volcano House since i875; and the greater part of the eleva tion has been effected the previous three years.
Captain Dutton ascribes the ebullition of the lava to steam and gases. Much of the visible steam comes from the fissures and numberless vent holes in the walls. Over the entire surface of the burning lakes is spread a pall of translucent vapor. Of the vapors he recognized the sulphur gases and considered that the bleaching of the brilliant orange and saffron colors of certain patches was due to hydrochloric acid.
To the southwest there existed another lake, which had been opened up about three years earlier, known as the "Old South Lake." Great quantities of pungent gas exclude from number less fissures, and the surface is hot. There are occasional small eruptions over its surface.