Chart of the Azimuth of Polaris for 1918

A chart titled "Plate X-Azimuth of Polaris." Handwriting on the back is mostly illegible but some read: "Fire 600 meters right, Montrebeau Wood, 15 min; North, 500 meters; 8090, 9090, 8085, 9085; F to right one sweep, D to left, E to right; guns laid for n. barrage same as yes...