Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . alloon is placed the valve, which is either inthe form of a disc or of the butterfly type. Strong springs areused to close it after it has been opened for any purpose, and thevalve is made tight by pressing its sharp edge against a rubberseating. It wasthe general cus-tom, years ago, tolute the valvewith some kind ofcement to make itfit tighter; butthis plan wasgiven up, as itwas found that thevalve no longerfitted tightly afterit had been onceopened. Th
Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . alloon is placed the valve, which is either inthe form of a disc or of the butterfly type. Strong springs areused to close it after it has been opened for any purpose, and thevalve is made tight by pressing its sharp edge against a rubberseating. It wasthe general cus-tom, years ago, tolute the valvewith some kind ofcement to make itfit tighter; butthis plan wasgiven up, as itwas found that thevalve no longerfitted tightly afterit had been onceopened. The valveis opened by acord, which passesthrough the infla-tion tube to thetop of the balloon. On the coveringthere is a strip,which begins at adistance of 20 the valve,and extends halfthe way down,gradually broad-ening towards the bottom; it is covered by a similar strip on the inside, the twobeing cemented to the envelope, but not sewn. At the momentof reaching the ground, this strip is ripped off by means ofa cord, and helps the balloon to empty suddenly. The dangerof bumping along the ground^is in this way generally Fit?. 110.—Balloon valves. 184 AIRSHIPS PAST AND PRESENT. In Germany, the ripping-cord is always used, because it ensuresa safer landing. A clever aeronaut with a little practice and withthe use of the ripping-cord can alight with certainty where hechooses, even in a strong wind; and this is a matter of greatimportance, particularly in order to avoid damage to growingcrops. Gusty winds often make the landing a matter of difficulty ;but in this way it is possible to descend suddenly on any con-venient spot that may present itself. As a matter of history, itmay be stated that the first man who was called upon to paydamages was Testu-Brissy in 1786. Of course the greater partof the damage was done by the rustics who flocked to see whatwas going on, as, indeed, always happens ; but Testu-Brissy wasexpected to make good all the havoc that had been
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