A Thousand Degrees Below Zero

From some point far overhead a musical humming became audible. It was not the rasping roar of an aëroplane motor, but a deep, truly melodious note that seemed to grow rapidly in volume. The soft-voiced conversations on the upper deck were hushed. Every one listened to the strange sound from above. It grew and became clear and distinct. The source seemed to come nearer. At last the sound came from ...