Night Balloon Ascents of Mr James Glaisher
Mr. Glaisher having, in one of his descents, which took place near sunset, observed that the temperature was the same through a very considerable height, it occurred to him that after dark it was quite possible that, for some elevation above the earth's surface, the temperature might even increase with increase of height; and to determine this he arranged for some ascents to be made after sunset, so that the temperature during the night might be observed. For this purpose he procured a couple of Davy lamps, which answered their object satisfactorily.
Accordingly, on October 2, 1865, an ascent was made from Woolwich Arsenal, the time of starting being about three-quarters of an hour after the sun had set. The temperature on the earth was 56°, and it steadily increased to 59°.6 at the height of 1900 feet. This was established conclusively by repeated ups and downs, the temperature falling as the balloon descended. The view of London lighted up, as seen from the balloon in this ascent, the night being clear, was most wonderful.
A second night ascent, was made from the same place on December 2, 1865, and the balloon left the earth 2 3/4 hours after sunset. On this occasion the temperature did not rise, but the decrease, though steady, was small.
In an ascent from Windsor on May 29, 1866, the balloon was kept up till half-past eight o'clock, and the temperature was found to decreased as the earth was approached during the last 900 feet.
In this last ascent no paid aeronaut was employed as Mr. Westcar, of the Royal Horse Guards, undertook the management of the balloon. In the preceding five ascents Mr. Orton, of Blackwall, was employed as aeronaut.
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