The next day they set out on their journey to that mountain, and the first part of their path lay over a gentle ascent, through cultivated grounds.  Next succeeded an almost perpendicular hill, bare of trees, and overgrown with a tall grass, which it was difficult to pass through.

Such had been the time taken up, that the party found it impossible to reach the summit and return before dark.  They therefore began to collect specimens; and after having obtained a full load, they returned late in the afternoon to Los Banos.

The mountain is composed of trachytic rocks and tufa, which are occasionally seen to break through the rich and deep soil, showing themselves here and there, in the deep valleys which former volcanic action has created, and which have destroyed the regular outline of the cone-shaped mountain.  The tufa is generally found to form the gently-sloping plains that surround these mountains, and has in all probability been ejected from them.  Small craters, of some two hundred feet in height, are scattered over the plains.  The tufa is likewise exposed to view on the shores of the lake; but elsewhere, except on a few bare hills, it is entirely covered with the dense and luxuriant foliage.  The tufa is generally of a soft character, crumbling in the fingers, and in it are found coarse and fine fragments of scoria, pumice, etc.  The layers are from a few inches to five feet in thickness.

In the country around Los Banos, there are several volcanic hills, and on the sides of Mount Maquiling are appearances of parasitic cones, similar to those observed at the Hawaiian Islands; but time and the foliage have so disguised them, that it is difficult to determine exactly their true character.

I regretted exceedingly that the party that set out for the Lake of Taal was not able to reach it, as, from the accounts I had, it must be one of the most interesting portions of the country.  It lies nearly south-west from Manila, and occupies an area of about one hundred and twenty square miles.  The Volcano of Taal is situated on an island near the center of it, and is now in action.  The cone which rises from its center is remarkably regular, and consists for the most part of cinders and scoria.  It has been found to be nine hundred feet in elevation above the lake.  The crater has a diameter of two miles, and its depth is equal to the elevation; the walls of the crater are nearly perpendicular, so much so that the descent cannot be made without the assistance of ropes.  At the bottom there are two small cones.  Much steam issues from the many fissures, accompanied by sulphurous acid gas.  The waters of the lake are impregnated with sulphur, and there are said to be also large beds of sulphur.  In the opinion of those who have visited this spot, the whole lake once formed an immense crater; and this does not appear very improbable, if we are to credit the accounts we received of the many craters on this island that are now filled with water; for instance, in the neighborhood of San Pablo there are said to be eight or nine.