Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . ts surfaces tillthey intersect the surface of the sphere. In this way, six squarepieces are formed with twelve dividing lines, three of which meetat a corner. It is easy to see from the diagram how the pieces areput together. The seams are covered with strips, both on theinside and outside, which are made to adhere with rubber the bottom of the envelope the tubular opening, used forinflation, is secured to a wooden ring. It is generally leftu
Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . ts surfaces tillthey intersect the surface of the sphere. In this way, six squarepieces are formed with twelve dividing lines, three of which meetat a corner. It is easy to see from the diagram how the pieces areput together. The seams are covered with strips, both on theinside and outside, which are made to adhere with rubber the bottom of the envelope the tubular opening, used forinflation, is secured to a wooden ring. It is generally leftunclosed, so that, as the balloon rises, the gas can freelyescape. A Frenchman, named Mallet, devised an arrangementby which air is prevented from being sucked into the balloon,and used it on one of his expeditions with success. He remainedin the air for 36J hours, and covered a distance of 560 neck is joined to the ring by ropes ; by cutting away theseropes the balloon will fall like a parachute, in case it should loseits gas. Fig. 109.—Professor Finster-walclers patterns for balloonenvelopes. BALLOON CONSTRUCTION, ETC. 183. At the top of the balloon 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 gro
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Keywords: ., bookcentury1900, bookdecade1900, bookpubl, booksubjectaeronautics
