1789. The staff is used in laying out straight lines. It may be a straight rod of six or eight feet long or upwards, and one inch in diameter; with the first six inches at the top painted white, the second black, and the third six inches red. Two points of the desired straight line being found or given, any greater number of points are found by placing other staffs or rods so as they shall range, and the first staff conceal from the eye, placed behind it, all the rest in the line: the use of the three different colours is to render the ends distinctly visible when the ground is fresh dug, white or covered with snow, or green, as in pastures.
