The elements of Euclid, explained and demonstrated in a new and most easie method with the uses of each proposition in all the parts of the mathematicks / by Claude Francois Milliet D'Chales, a Jesuit ; done out of French, corrected and augmented, and illustrated with nine copper plates, and the effigies of Euclid, by Reeve Williams ...

USE.

THis Proposition is of a great extent, and may pass for a universal Princi∣ple in all sorts of Measuring. For in the first place the ordinary practice in measu∣ring inaccessible Lines, by making a little Triangle like unto that which is made or imagined to be made on the ground, is founded on this Proposition, as also the greatest part of those Instruments, on which are made Triangles like unto those that we would measure, as the Geometrical Square, Sinical Quadrant, Jacobs Staff, and others. Moreover we could not take the plane of a place, but by this Proposi∣tion: wherefore to explain its uses, we should be forced to bring in the first Book of practical Geometry.