36 DICTIONARY OF AVIATION
1. a relativly small balloon or air-bag placed inside a larger balloon or aerostat and used for controlling the alti- tude or for keeping the envelop taut.
2. one of several subsidiary balloons or inflated gas-bags forming compartments or structural units in a dirigible balloon, for the purpose of safety in case of accident, or for insuring stability of form.
ballounet ,bael9'net n. see ballonet.
ballon sonde ,b3elon's0rjd n. [also spelt ballon-sonde; plural
ballons sondes] same meaning as sounding-balloon. , balloon bo'luun n.
1. (in fireworks) a pasteboard ball stuft with combusti- bles, fired from a mortar to a considerable height where it bursts and produces various luminous effects; an air-bal- loon (sense i).
air balloon, same meaning as air-balloon (sense i).
2. an airtight bag or hollow vessel fild with hydrogen gas, coal-gas, heated air, or any other gas lighter than common air, and often provided with a car and other appurtenances designed to rise and float in the atmosfere, alone or with persons on board.
air balloon, same meaning as air-balloon (sense 2).
auxiliary balloon, a balloon used in an auxiliary or secondary capacity.
balloon photography, fotegrafy from balloons; the art of taking fotografic pictures while traveling in a balloon.
balloon principle, the principle of the balloon or aerostat ; the principle of atmosferic buoyancy; the lighter-than-air idea : distinguisht from flying principle.
captiv balloon, see under captiv.
coal-gas balloon, a balloon whose gasbag is inflated with coal-gas.
dirigible balloon, a balloon which can be steerd or guided ; a steerable balloon; a dirigible.
elongated balloon, a balloon tohich, insted of having a globular or pear-shaped gasbag, is longer than it is wide; a cylindric, cigar-shaped, or sausage-shaped balloon or diri- gible.
free balloon, a balloon which is free from all connection with, or attachment to, the earth : distinguisht from cap- tiv balloon; also, an unmanned balloon, free from control, used for investigating the upper air.
heated-air balloon, same meaning as hot-air balloon.
hot-air balloon, same meaning as fire-balloon, compare air-balloon (sense 2).
hydrogen balloon, same meaning as hydrogen-balloon.
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