This floor of lava, which seems likely to be a more or less permanent feature, was, three or four years ago, upon a level with the top of the high ridge, or ledge, whose base you skirt.  The main part of the crater was then a floor of lava vaster even than it now is.  Suddenly one day, and with a crash which persuaded one or two persons at the Volcano House that the whole planet was flying to pieces, the greater part of this lava floor sank down, or fell down, a depth of about five hundred feet, to the level whereon we now walked.  The wonderful tale was plain to us as we examined the details on the spot.  It was as though a top-heavy and dried-out pie-crust had fallen in in the middle, leaving a part of the circumference bent down, but clinging at the outside to the dish.

[Illustration:  LAVA FIELD, HAWAII—­FLOW OF 1868.]

After this great crash the lava seems from time to time to have boiled up from beneath through cracks, and now lies in great rolls upon the surface, or in the deeper cracks.  It is related that later the lake or caldron at the farther end of the crater boiled over, and sent down streams of lava which meandered over the black plain; that, continuing to boil over at intervals, this lake increased the height of its own banks, for the lava cools very rapidly; and thus was built up a high hill, which we ascended after crossing the lava plains, in order to look down, in fear and wonder, upon the awful sight below.  What we saw there on the 3d of March, 1873, was two huge pits, caldrons, or lakes, filled with a red, molten, fiery, sulphurous, raging, roaring, restless mass of matter, to watch whose unceasing tumult was one of the most fascinating experiences of my life.

The two lakes were then separated by a narrow and low-lying ledge or peninsula of lava, which I was told they frequently overflow, and sometimes entirely melt down.  Standing upon the northern bank we could see both lakes, and we estimated their shortest diameter to be about 500 feet, and the longest about one-eighth of a mile.  Within this pit the surface of the molten lava was about eighty feet below us.  It has been known to sink down 400 feet; last December it was overflowing the high banks and sending streams of lava into the great plain by which we approached it; and since I saw it, it has risen to within a few feet of the top of the bank, and has forced a way out at one side, where, in September, 1873, it was flowing out slowly on to the great lava plain which forms the bottom of the main crater.

What, therefore, Madame Pele will show you hereafter is uncertain.  What we saw was this:  two large lakes or caldrons, each nearly circular, with the lower shelf or bank, red-hot, from which the molten lava was repelled toward the centre without cessation.  The surface of these lakes was of a lustrous and beautiful gray, and this, which was a cooling and tolerably solid scum, was broken by jagged circles of fire, which