In this ascent six pigeons were taken up.
One was thrown out at three miles. It extended its wings, and
dropped like a piece of paper. A second at four miles, and it
flew with vigour. A third between four and five miles, and it
fell downwards. A fourth was thrown out at four miles in
descending, and it alighted on the top of the balloon. Two were
brought to the ground. One was dead, and the other was ill, but
recovered so as to fly away in a quarter of an hour."
The results gathered by Mr. Glaisher from his numerous ascents
are very interesting. He found that in no instance did the
temperature of the air decrease uniformly with the increase of
height. In fact, the decrease in the first mile is double that
in the second, and nearly four times as great as the change of
temperature in the fifth mile. The distribution of aqueous
vapour in the air is no less remarkable. The temperature of the
dew-point on leaving the earth decreases less rapidly than the
temperature of the air; so that the difference between the two
temperatures becomes less and less, till the vapour or cloud
plane is reached, when they are usually together, and always most
nearly approach each other, and that point is usually at about
the height of one mile.
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