A flight log kept by the navigator of the Enola Gay, the plane that dropped the atom bomb on Hiroshima, has sold for $372,500.

The lot headlined a sale of books and Americana at Sotheby's yesterday.

The Enola Gay dropped the first atomic bomb on Japan on August 6, 1945

Captain Theodore "Dutch" Van Kirk was of nine members of the crew aboard the bomber, which took off from an American airbase on Tinian Island in the Pacific in the early hours of August 6, 1945.

Sotheby's comments: "At 0915½ (30 seconds past 8:15am Hiroshima local time) in the position field Van Kirk notes the action that would end the war and change the world forever, 'Bomb Away', further writing in the remarks field 'Circle E of Target.'

"By 0931 they were flying over Mishima, and just past 29° 43' E 137° 03' E, a little over an hour and a half later, Van Kirk notes '10:52 - Cloud Gone'."

The bomb, and the one dropped on Nagasaki three days later, effectively ended the war overnight.

This had the effect of saving millions of lives on both sides, but came at a terrible cost. Around 90,000-140,000 people are believed to have perished in the attacks.

Many more lives were dramatically shortened from exposure to radiation.

Van Kirk (who died in 2014) explained in a 2005 interview with TIME magazine: "You fight a war to win. There were over 100 numbered military targets within the city of Hiroshima.

"It wasn't a matter of going up there and dropping it on the city and killing people.

"It was destroying military targets in the city of Hiroshima — the most important of which was the army headquarters charged with the defense of Japan in event of invasion."