CHAPTER XI
BALLOONS AND PARACHUTES.
Balloons that really go up are always attractive but by thoughtful planning they can be made much more beautiful. A nice white balloon against a blue sky is very pleasing, but most boys like more color. The hot air balloons are made of tissue paper, and consist of an inverted bag with a light piece of reed at the bottom to keep the mouth open. The most successful shape is shown by Fig. 184. This need not be perfectly round on top, but may be pointed, as in Fig. 185. If the balloon is too nearly round like a ball, it is liable to turn over and allow the hot air to escape. If the balloon is too long and slender vertically, it would probably flounder around in the breeze too much. There is not the variety possible in balloons that there is in kites, as no ballast can be attached that is of much service. In some shapes only a very little is necessary to keep them in an upright position, in this case a little ballast will suffice, and a number of shapes can be made with this addition. The ballast should be suspended by strings from the reed at the bottom, see Fig. 186. The ballast may only be a piece of cardboard, but in some cases that little is very necessary.
Some of the boys try models of the dirigible, but usually they get something too large for hot air manipulation. The dirigible is more of a cigar-shaped balloon. Strings run down to a framework that carries the propellor, which is a paper windmill in this case, but it is very difficult to keep these representative parts light enough to be carried by the hot air medium.
In making a balloon like Fig. 184 the covering is made in tapering sections. The pattern given is for a five-foot balloon. The width at the lower end of the section is five inches, three feet farther up fifteen inches, and it comes to a point at the top. The edges of these sections form a long curve, Fig. 187. Five feet would require just a little over two lengths of tissue paper. There are seven sections in the balloon.
Inflation. Two methods are used to fill the balloons. A wire is stretched across the frame of the mouth of the balloon and another at
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