Original World War 2 air conditioning industry trade magazine vintage ad for YORK ICE MACHINERY CORPORATION of York, PA. Helping Gunners See The Invisible! It takes good eyesight and good instruments to hit targets you can't see! Mergenthaler has turned its skilled workers and precision machinery to the making of artillery fire control instruments. And Mergenthaler called upon York engineers and experience in industrial air conditioning to provide a controlled, cool, dry, dust free climate for the assembly of these instruments. Old 1943 WW2 wartime era propaganda magazine advertisement.