Note F — ITALY AT WAR (continued 3)

In order to keep pace with the steady improvement in range and accuracy of anti-aircraft artillery, aviators have found it necessary to operate at constantly increasing altitudes, so that it is now not uncommon for aerial combats to be fought at a height of 20,000 feet. Hence, many airplanes are now equipped with oxygen-bags for use in the rarefied atmosphere of the higher levels. The aviators operating on the Italian front experience such intense cold during the winter months that a system has been evolved for heating their caps, gloves, and boots by electricity generated by the motor.