From their neat wooden boxes were taken two highly polished brass instruments, each of which was provided with a telescope. One of these was a transit, for laying off lines, angles, and curves on the surface of the earth; and the other was a level for measuring the height of elevations or the depth of depressions on this same surface. As these instruments were lifted carefully from their boxes they were screwed firmly to the tops of wooden tripods, that supported them at the height of a man's eyes.