Ferris, Richard. [from old catalog] · New York, T. Nelson and sons · leaf 43
uch machinery willhave weight, and the bag of gas must be enlarged tocounterbalance it. When this is done, the man andthe bag of gas may move through the air, and withsuitable rudders he may direct his course. This com-bination of the lifting bag of gas and the propellingmachinery constitutes the… … -^$S
Aeronautics
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