This kind of work cannot be delegated to anyone, and besides the arduous labor involved in climbing the huge trees, there are other serious annoyances connected with it. The climber is almost certain to disturb some venomous insect which revenges itself by a savage sting which has to be endured; or he may rend clothes and skin also, on some thorny vine, or another, crushed by his efforts, may exude a juice which will leave him tattooed for days; then, though there may not be a mosquito or fly at the base of the tree, the top will be infested with myriads of minute black flies, which cover hands and face, and with extremely annoying results. On the other hand the explorer may as a compensation have his nostrils filled with the perfume of some brilliant orchid on a neighboring branch; and there is a breezy enjoyment in watching the showers as they rush across the green carpet, and in listening to the roar with which the big drops beat upon the tree tops. The special phase of field work which fell to my personal lot was entirely reconnaissance, consisting of canoe examinations of all streams in the vicinity of the line of the canal, to determine their sources, character of valley, and approximate water shed; of rapid air-line compass and aneroid trails, to connect one stream, or valley head with another, or furnish a base line for a general sketch plan of a valley; and of studies of the larger features of the terrene, from elevated tree tops. The last has been already described; in the second the experience was very similar to that of the parties in running main lines. On these occasions three or at most four hardy _huléros_ (rubber hunters) comprised the party, two carrying the blankets, mosquito bars and provisions for several days, and one or two cutting the lightest possible practicable trail and marking prominent trees. In a day's march of from five to eight miles, and this was the utmost that even such a light, active and experienced party could cover in one day, every possible and some almost impossible kinds of traveling was encountered, and thoroughly exhausted men crept into their bars every night. The canoe reconnaissances were more agreeable, though some most unpleasant as well as most enjoyable memories are connected with them. The innumerable large fallen trees which obstruct the streams and over or through which the canoe must be hauled bodily, the almost inevitable capsizing of the canoe, the monotonous red clay banks on either side and the frequent necessity of lying down at night in a bed of mud into which the droves of wild pigs which inhabit these valleys have trampled the clayey soil, are among the disagreeable incidents. From the head of canoe navigation to their sources the character of these streams is entirely different, and both in 1888 and in 1885 I have followed them far up into mountain gorges, the beauty of which is as fresh in my memory as if I had been there but yesterday.