Device to learn to obtain readings on topographical sight with the help of a reticle (Machine-translation by Google Translate, not legally binding)

摘要

A device to learn to obtain readings on topographical sight with the help of a reticle characterized by a sheet where small scale topographic sights are printed and scales of representation of degrees and a box or flat bag where the sheet slides so that it can leave at both ends. (Machine-translation by Google Translate, not legally binding)