Evening Republican, Volume 21, Number 246, Rensselaer, Jasper County, 19 October 1918 — TRAVEL ACCORDING TO MAP [ARTICLE]

TRAVEL ACCORDING TO MAP

Airmen on Night Raids Have Course Thoroughly Mapped Out Before Beginning Their Journey. Before leaving on a long-distance night raid the airmen prepare their maps with great care, marking on them the detailed course from the airdrome to their objective. By means of a small balloon, whose speed direction and height is recorded by an instrument on the ground, the force and direction of the wind at different altitudes is discovered, and the compass course, allowing for winddrift, is marked beside the course on the map. The compass course for the return Journey is also marked. The speed of the machine is calculated, and on the line of the course a series of points is marked, showing where the machine should be every ten minutes, thus enabling the airman to check his progress and to know his approximate position if he gets lost. He watches the country below for landmarks. He sees by his map that a river should appear in a few minutes. His watch shows that he has been flying 40 minutes, and near the 45-mlnute mark on his map is a twisted pale blue line. He looks ahead and sees in the moonlight a silver streak and he knows he is making good time. When he is over the river he compares s its outline with his map, and sees that he ! is crossing it at the right place.