BALLOONING, MODERN. 



71 



BALLOONING, MODERN. Practical bal- 



|i ionium enmpn>es I Kith the manufacture and the 

 l>alli">n-. There are two kinds of balloon 

 the hydrogen or gas balloon, and the Mont- 

 giillter IT hot-air balloon. The former is the 

 inn-it iMi|Mirt!int, and claims the greater part of 

 uiir attention here. 



A complete hydrogen balloon consists of the 

 gas en veli ipe and \al\e. netting and ropes, wicker 

 ear, coneentrating ring, and anchor, to which 

 may lie added a drag rope and a collapsing cord. 

 Km- inflation pure nydrogen gas is used, also 

 carbureted hydrogen or coal gas, and sometimes 

 wnt i-r gas. Sand bugs are required to retain the 

 balloon in position during inflation, and more or 

 less sund is usually curried in the car as ballast. 

 Kvery aeronaut should be capable of making his 

 own balloon, but, in the almost total absence of 

 practical information, most of them become old 

 before learning all that is necessary on the sub- 

 ject. Silk, linen, or cotton, or combinations of 

 these, are the fabrics we have to deal with for 

 the manufacture of the envelope or gas holder. 

 The best of these is silk, of which there are 

 many kinds that answer equally well. Linen, 

 at first sight, would seem to be the next best 

 material for balloon construction, but expe- 

 rience has proved otherwise ; the fabric is 

 heavy, and becomes hard and brittle when var- 

 nished, and a balloon made of it is continually 

 breaking into holes. Cotton, of various weights 

 and makes, is most in use, because it is cheap, 

 will last as long as the oil varnish, and answers 

 I'very purpose in ordinary ballooning. Strength 

 is obtained by using the heavier qualities, and 

 almost any degree of lightness may be had by 

 using the finer grades. The best heavy cotton 

 for this purpose is the bleached Wamsutta 

 sheeting. It is a common error to suppose that 

 unbleached cotton is more suitable for the pur- 

 pose than bleached. It is possible that a half- 

 bleached cloth might be stronger, but the spongi- 

 ness of unbleached goods is detrimental to their 

 use. Wamsutta, however, on account of its 

 weight, is suitable only for very large balloons. 

 Lonsdale sheeting is lighter and better adapted 

 to medium sizes. Lonsdale cambric is still 

 lighter, and may be used for balloons of twenty- 

 five or thirty thousand cubic feet capacity. The 

 proper shape of balloons for economy in mate- 

 rial, weight, and gas, as well as for facility in 

 management, is globular, and consequently" we 

 shall consider no other. 



The first thing in order is to ascertain the 

 quantity of cloth required, which may be done 

 in the following manner: To determine the 

 number of breadths, divide the circumference in 

 inches by the number of inches in width of ma- 

 terial, deducting one inch for each seam. The 

 length of the gores will be equal to half the cir- 

 cumference. Multiply the number of breadths 

 by the number of yards in the length of a gore; 

 deduct one fourth'of the product, and the rrsult 

 will be the total quantity in yards required to 

 make the balloon. The following rules will be 



found useful in determining the size of the bal- 

 loon required. To obtain the niMiil>er of cubic 

 feet in a sphere, multiply the surface by one 

 sixth of the diameter. To determine the num- 

 ber of square feet in the surface of a sphere, 

 multiply the diameter in feet by the number of 

 feet in the circumference. 



The Pattern. For a pat tern use manilla roll 

 paper of sufficient length and width. At one 

 end of the paper write " tip," and at the other 

 "neck": then draw the following lines: First 

 one running from end to end, an inch from one 

 of the edges. Measure from tip to neck the 

 exact length of the gore as previously calculated, 

 and add three inches for loss by seams. Divide, 

 with a pair of compasses or other convenient 

 instrument, the whole length into thirty-six 

 equal parts, and draw lines across the paper at 

 the points of division. Then take a strip of 

 paper or wood one inch wide and one inch less in 

 length than the width of the paper or the cloth, 

 and with a pencil make a measure by dividing 

 the strip into ten equal parts ; subdivide these 

 each into ten parts ; and, lastly, divide these sub- 

 divisions each into ten parts. Thus we shall 

 obtain a scale of one thousand parts. For con- 

 venience we shall call the divisions on the scale 

 " marks," counting from 1 to 1,000. With this 

 measure we can determine the points through 

 which the curve line of the pattern must pass. 

 Place the end of the scale or measure at the line 

 first drawn, one inch from the edge of the paper, 

 near the tip end and beside line No. 1. The 

 length of this line to the point through which 

 the curve passes will be 87 marks ; with a pencil 

 make a cross at the point, and proceed to line 

 No. 2, which will be 173 marks in length, and 

 so on, connecting afterward the points thus 

 marked by a curve line. If the balloon is to be 

 made perfectly round, with a cylindrical neck 

 attached, the pattern must be pointed at both 

 ends; but if it is to be slightly elongated at the 

 bottom, with a gradual development of the neck, 

 the pattern is extended in length and the curve 

 gradually turned outward, as in the diagram. 

 The pattern must be cut along the curve line. 

 Lay out the cloth on a long table, and cut into 

 lengths of a little over two thirds that of the 

 pattern, or exactly eight inches below line 24, 

 and call the end the "butts." Lay the pieces 

 successively one upon another until all are down, 

 taking care that the edges on one side are kept 

 even. On the cloth thus arranged lay the pat- 

 tern even with the butts, and after putting 

 weights upon it proceed to cut. with a knife ana 

 straight-edge, through all the layers at once, con- 

 tinuing from point to point along the curve. 

 After cutting it will be necessary, for the guid- 

 ance of the sewers, to mark with a pencil each 

 layer of the cloth, on both edges, at the ends of 

 the cross lines from 1 to '24. The pieees cut 

 from the tip to the equator are to IM> rvad justed 

 with the broad end-; evenly mat died and their 

 edges arranged as before. Reverse the pattern 

 and place line 12 at the butts, and with the 



