136 Kilauea and Mautia Loa. 



once, and the impression the sight convej'ed was of a black hand gently passing under 

 the heav3' block and raising it or carrj'ing it along. In the same vva}- lava has insinu- 

 ated itself beneath stone walls built to bar its progress and lifted and overthrown the 

 futile barrier. So extensively has this process been at work in Kilauea that my sur- 

 ve}- of the crater, made with great care in 1S65, and six years later adopted by the 

 Trigonometrical Survey of the Hawaiian Government and republished on their official 

 map, is already antiquated except in a few points, ascertained by my monuments still 

 standing; the whole boundarj- has perceptibly changed, and I consider Kilauea nearly 

 five per cent, larger than it w^as eighteen years ago. The change visible on the bottom 

 of the crater was even greater. I was provided with an excellent barometer, by the 

 kindness of vny friend Mr. Carpenter, and found by it that while the bottom of the 

 crater, at the base of the outer wall where first reached in our descent, was 650 feet 

 below the Volcano House, the central portion was only 300 feet, or, in other words, 

 the floor was raised in the general shape of a flat dome 350 feet high. Nor was this 

 hill of lava simply the overflow of the lakes whence the lava runs in frequent out- 

 breaks ; the mass was partly composed of these numberless little overflows, but the 

 great mass was evidentl}' elevated in the centre, and the cracks everywhere indicated 

 that this elevation was not a slow cumulative action, but had been, at intervals, greatly 

 and irregularl}' accelerated. 



In 1865 the floor of the crater was verj' irregular, full of caves and intersedled 

 by great cracks, but its general surface was nearly horizontal. A few years later the 

 floor fell in over about a third of its area (see Fig. 69, p. 107 ) and the caves and cracks 

 were alike obliterated, a funnel-like depression with but slight signs of fire at the bot- 

 tom. The action, however, continued until the tunnel was not only filled up but the 

 overflow from it reached the outer walls of Kilauea, and then, for a while, the action 

 decreased and the lava cooled. A renewal of activity floated this crust as is indicated 

 by occasional outflows at the edges, and so the intermittent action had in 1880 formed 

 a tolerably regular dome surrounded b};- four lakes (the latest on the southeast began 

 to form on May 15th) of an average diameter of a thousand feet each. The walls of 

 these lakes of fire were much broken and changing daily. They were elevated in 

 places far above the contour of the dome, and from the action of heated vapors, were 

 decomposed until their layered strudlure was plainly visible at a distance by the bands 

 of brilliant colors not unlike those of the clay cliffs at Gay Head on Martha's Vine- 

 yard. Bmerald-green, vermilion, bli;e and Indian-j^ellow, irregularl}- distributed, 

 indicated either very little homogeneity of the masses or uncertain action of the 

 sulphurous and acid vapors. [514I 



