National Geographic : 1933 Apr
AIRPLANES AND DOG SLEDS ARE USED FOR TRANSPORT AMONG THE GOLD FIELDS OF NORTHERN CANADA Miners, tools, .upplies, dogs, and even the sleds are often carried by air. These planes have landed on afrozen lake, whence dog teams setout. Then the planes are left behind, motors are drained of oil and covered with tarpaulin. They are anchoredbypouring water ontheskis and freezing them to the surface. Before starting again, oil is heated and poured into the motors.