In 1885 the party of which I was a member pushed a nearly direct line across the country from a point on the San Juan, about three miles below the mouth of the Rio San Carlos, to Greytown, a distance of thirty-one miles by our line, as compared with fifty-six miles by the river and forty-two miles by the former proposed canal route. In December, 1887, I went out in charge of a final surveying expedition, consisting of some forty engineers and assistants and one hundred and fifty laborers, to resurvey and stake out the line of the canal preparatory to the work of construction. The information and personal experience gained in previous surveys made it possible, without loss of time, to locate the various sections of the expedition in the most advantageous manner, and push the work with the greatest speed consistent with accuracy. The location lines of the previous surveys were taken as a preliminary line and carefully re-measured and re-levelled. Preliminary offsets were run; the location made, and staked off upon the ground; offsets run in from three hundred to one hundred feet apart, extending beyond the slope limits of the canal; borings made at frequent intervals; and all streams gauged. The result of this work was a series of detail charts and profiles, based upon rigidly checked instrumental data, and covering the entire line from Greytown to Brito, from which to estimate quantities and cost. As may be imagined by those familiar with tropical countries, the prosecution of a survey in these regions is an arduous and difficult work, and one demanding special qualifications in the engineer. His days are filled with a succession of surprises, usually disagreeable, and constant happenings of the unexpected. Probably in no other country will the traveler, explorer, or engineer, find such an endless variety of obstacles to his progress. Every topographical feature of the country is shrouded and hidden under a tropical growth of huge trees and tangled underbrush, so dense that it is impossible for even a strong, active man, burdened with nothing but a rifle, to force himself through it without a short, heavy sword or _machéte_, with which to cut his way. Under these circumstances the most observant engineer and expert woodsman may pass within a hundred feet of the base of a considerable hill and not have a suspicion of its existence, or he may be entirely unaware of the proximity of a stream until he is on the point of stepping over the edge of its precipitous banks. The topography of the country has to be laboriously felt out, much as a blind man familiarizes himself with his surroundings. In doing this work the indispensable instrument, without which the transit, the level, and indeed the engineer himself is of no use, is the national weapon of Nicaragua, the _machéte_, a short, heavy sword.