The limestone mountains, though of great extent, seem to be entirely superficial, resting on a basis of basalt which in some places forms low rounded hills between the more precipitous mountains. In the rocky beds of the streams basalt is almost always found, and it is a step in this rock which forms the cascade already described. From it the limestone precipices rise abruptly; and in ascending the little stairway along the side of the fall, you step two or three times from tpe of rock on to the other--the limestone dry and rough, being worn by the water and rains into sharp ridges and honeycombed holes--the basalt moist, even, and worn smooth and slippery by the passage of bare-footed pedestrians. The solubility of the limestone by rain-water is well seen in the little blocks and peaks which rise thickly through the soil of the alluvial plains as you approach the mountains. They are all skittle-shaped, larger in the middle than at the base, the greatest diameter occurring at the height to which the country is flooded in the wet season, and thence decreasing regularly to the ground. Many of them overhang considerably, and some of the slenderer pillars appear to stand upon a point. When the rock is less solid it becomes curiously honeycombed by the rains of successive winters, and I noticed some masses reduced to a complete network of stone through which light could be seen in every direction.
From these mountains to the sea extends a perfectly flat alluvial plain, with no indication that water would accumulate at a great depth beneath it, yet the authorities at Macassar have spent much money in boring a well a thousand feet deep in hope of getting a supply of water like that obtained by the Artesian wells in the London and Paris basins. It is not to be wondered at that the attempt was unsuccessful.
Returning to my forest hut, I continued my daily search after birds and insects. The weather, however, became dreadfully hot and dry, every drop of water disappearing from the pools and rock-holes, and with it the insects which frequented them. Only one group remained unaffected by the intense drought; the Diptera, or two-winged flies, continued as plentifully as ever, and on these Iwas almost compelled to concentrate my attention for a week or two, by which means I increased my collection of that Order to about two hundred species. I also continued to obtain a few new birds, among which were two or three kinds of small hawks and falcons, a beautiful brush-tongued paroquet, Trichoglossus ornatus, and a rare black and white crow, Corvus advena.
At length, about the middle of October, after several gloomy days, down came a deluge of rain which continued to fall almost every afternoon, showing that the early part of the wet season had commenced. I hoped now to get a good harvest of insects, and in some respects I was not disappointed. Beetles became much more numerous, and under a thick bed of leaves that had accumulated on some rocks by the side of a forest stream, I found an abundance of Carbidae, a family generally scarce in the tropics. The butterflies, however, disappeared. Two of my servants were attacked with fever, dysentery, and swelled feet, just at the time that the third had left me, and for some days they both lay groaning in the house. When they got a little better I was attacked myself, and as my stores were nearly finished and everything was getting very damp, I was obliged to prepare for my return to Macassar, especially as the strong westerly winds would render the passage in a small open boat disagreeable, if not dangerous.
Since the rains began, numbers of huge millipedes, as thick as one's finger and eight or ten inches long, crawled about everywhere--in the paths, on trees, about the house--and one morning when I got up I even found one in my bed! They were generally of a dull lead colour or of a deep brick red, and were very nasty-looking things to be coming everywhere in one's way, although quite harmless. Snakes too began to show themselves. Ikilled two of a very abundant species--big-headed, and of a bright green colour, which lie coiled up on leaves and shrubs and can scarcely be seen until one is close upon them. Brown snakes got into my net while beating among dead leaves for insects, and made me rather cautious about inserting my hand until I knew what kind of game I had captured. The fields and meadows which had been parched and sterile, now became suddenly covered with fine long grass; the river-bed where I had so many times walked over burning rocks, was now a deep and rapid stream; and numbers of herbaceous plants and shrubs were everywhere springing up and bursting into flower. I found plenty of new insects, and if I had had a good, roomy, water-and-wind-proof house, I should perhaps have stayed during the wet season, as I feel sure many things can then be obtained which are to be found at no other time. With my summer hut, however, this was impossible. During the heavy rains a fine drizzly mist penetrated into every part of it, and I began to have the greatest difficulty in keeping my specimens dry.
Early in November I returned to Macassar, and having packed up my collections, started in the Dutch mail steamer for Amboyna and Ternate. Leaving this part of my journey for the present, I will in the next chapter conclude my account of Celebes, by describing the extreme northern part of the island which I visited two years later.