National Geographic : 1942 Jun
() .National Ueograpfic Society ndUUicllrume uyjuis iviaraen From a Battered Airplane Carcass, Student Observers Spot Shell Bursts of aMiniature Sea Battle They use binoculars and range finders from a scale height of 2,000-3,000 feet at Trinidad's Royal Naval Air Station. The students find therange ofwooden "shell bursts" straddling models of German war vessels. Blue-and-white disks represent newly subsided salvos; white disks, earlier shots. Trailing tapes simulate ships' wakes.