Abstract
As a member of the oceanic department of the. Japanese Students League of Aviation, I (Satô) have practised the art of flying, since July, 1934, as I have a deep interest in aviation psychology.
I have found that an aviator can not do without a keen sense of depth, namely, the ability to discriminate keenly the degree of unevennesis of the ground. On the 26th December, 1935, I tried to rise up to a height of about 3,000 metres over IIanedaAerodrOlne in a training machine of the Mongs III type, and to discriminate the difference of heights of objects. it was glorious weather.
When my aeroplane, in ascending, had just come to the point where it was no more possible to distinguish the difference of heights of objects, it altitudes were as follows (the horizontal distance between the two respective objects was within 10 metres):
1) The surface of a lawn and an aeroplane flying above it (3-4 metres high) 150m.
2) An iron pipe (about 10m. high) and a cottage (5m.high)200m.
3)The ground and the electric wires over it 150-300m.
4) A pine tree (10 m. high) and a lodge (4 m. high) 300m.
5) The difference between the heights of roofs of ordinary houses 700m.
6) The surface of the sea or of a lawn and an aeroplane flying at an altitude of 150 to 200m 750m.
7) The difference between the roof (10m. high) and the chimney of a factory 850m.
8) The surface of an aerodrome and an aeroplane flying at an altitude of 200m 1,100m.
9) The ground and various flying aeroplanes 1,300m.
10 The heights of the hills near Ohmori 1,800m.
11) The ground and the gas-tank (40m high) near the coast of Omori 2,200m.
Since the records indicating the altitude of over 1,000 metres are not of full certainty, they ought to be tested once more by a series of experiments at some future time. And yet it will be necessary to take various weather conditions into consideration, and to make experiments with a subject who is ignorant of the sizes of the landmarks.
