BALLOONING, MODERN. 



73 



ami liable tn crack. Those colors should be 



i \\ilh March tif alu'iil the coiiM-lency "I' 



ih.it iiM-d in tin- laundry, and the combination 



i made while the starch is hot. The 



may hu applied with broad, flat brushes, 



though almit any kind of painter's brush will 



r, and win-re t ho saint) figure is to In- n- 



1 man\ times slcii'-ils cut from oiled or 



varnished paper may be used. 



The ornamentation completed, all the parts 

 arc ti> IK- j. lined together. First the lower ones 

 are to be sewed to the upper portions by a cross 

 at the buttings, taking care to match all 

 the -cams to one another perfectly. This done, 

 the t wohalvesonly remain lorclosing. Heretofore 

 till tlu- scams have passed over the sewing ma- 

 chine in a continuous way from front to back, 

 while the closing seams are done by bringing 

 Cm-ward small portions at a time from behind 

 the machine, llegin by sewing at the tip on 

 the first row, but only 2 yards before turning 

 over and sewing down the reverse side, join to- 

 gether such stays as have been included, con- 

 tinue the sewing, reversing and joining the 

 stays 2 yards at a time all the way down, and 

 then treat the last seam in like manner, begin- 

 ning at the tip and sewing downward. The top 

 of the balloon should be lined with an extra 

 thickness, 6 to 8 feet across. At the junction 

 of the seams a round hole is to be cut to admit 

 the valve. A disk of leather having an upright 

 collar attached, and resembling a broad-brim hat 

 without a crown, is stitched on around the open- 

 ing, ready for the introduction of the valve. 



The Varnish. The balloon must be coated 

 with some suitable material for closing the in- 

 terstices of the fabric, to give it gas-retaining 

 qualities. A nearly perfect skin, or film, is 

 aimed at, and this may be obtained in various 

 ways, but the only materials that seem practi- 

 cally suited to this purpose are linseed oil and 

 India rubber. The former is by far the easiest 

 of application, while the latter makes much the 

 lightest weight balloon. Linseed oil is brought 

 to the right consistency for forming a flexible 

 varnish of quick-drying properties by prolonged 

 heat or long exposure and frequent stirring in 

 the open air. Fine, limpid oil, made from Cal- 

 cutta seed, gives the best results. A copper 

 kettle must be used for the process, as iron is 

 liable to oxidation, which ruins the varnish. The 

 kettle must not be filled by at least one fifth of 

 its capacity, as the oil swells with the heat and 

 is liable at certain stages to foam. The kettle 

 may be permanently fixed and the fire made 

 movable, or the kettle may be movable and the 

 fire a fixture, but one or the other is ntveary. 

 The heating should be governed by the aid of a 

 thermometer, and must never be allowed to rise 

 to 500 F., as it is liable to burst out into flame; 

 but it may be allowed to rise to 400 with safety, 

 and if run at this heat for twenty-four hours will 

 be sufficiently done to answer the purpose. When 

 cool it will be as stiff as the thickest molasses in 

 cold weather, and quite stringy when tried be- 

 tween the thumb and finger. Constant stirring 

 while over the fire is beneficial, and the oil should 

 never be covered except to raise the heat to the 

 required degree. At 212 the water contained in 

 the oil boils off, and later, as the heat ri>es. a 

 liver-like substance is formed in the oil, unless it 



is kept stirred, but this substance mlissolveg, 

 and need cause no uneasiness. No addition to 

 the oil seems to be of the slightest advantage, 

 and the purer it hi kept from all contamination 

 the better it is. A slight addition of sulphur 

 prevents foaming and allows the raising of the 

 neat to a greater degree, but the addition of sul- 

 phur would be likely to cause a corrosive action 

 on the fiber of the balloon. 



The thick oil varnish is to be thinned down 

 when wanted fur use by the addition of benzine 

 until it will sprinkle freely through a watering 

 pot with a tolerably fine rose. 



The balloon is now stretched out at full length, 

 and folded one breadth upon another. When 

 this has been accomplished, take the watering 

 pot and sprinkle the top layer, using judgment 

 as to the quantity required to give the first coat- 

 ing. When this is done, turn over the first layer, 

 treating the subsequent ones in like manner, un- 

 til all have been sprinkled. Then, while it is 

 still wet with the mixture of benzine and oil, 

 begin at the tip end and roll the balloon up 

 tightly. Give it an occasional turn over, so that 

 the diluted oil may permeate every part. These 

 operations must not take place in the sun, or it 

 will not be safe to roll up the balloon, for fear of 

 spontaneous combustion. After the lapse of 

 several hours the balloon may be unrolled and 

 opened, when the oil will be found well soaked 

 through the entire fabric. If any bare places 

 show themselves, they are readily covered. Dry- 

 ing in the shade is to be preferred when time is 

 no object ; but when it is, the sun accelerates the 

 process. The first coating should have time, if 

 possible, to season in the shade after it has been 

 dried in the sun, as spontaneous combustion is 

 less likely to occur when the first coat has had 

 time to harden. The subsequent coats may be 

 put on in the same manner as the first, or the 

 work may be hastened by two men following the 

 sprinkler with soft brooms, for the purpose of 

 distributing the oil equally to every part. As 

 many as four coats will be required to make the 

 balloon sufficiently gas tight. 



Spontaneous Combustion. It should be un- 

 derstood that oil varnishes, when applied to 

 fabrics of any kind, are liable to spontaneous 

 combustion, the tendency being increased when 

 the drying has been done by artificial heat, or in 

 the sun. This liability passes awav in a few 

 weeks, but until the seasoning has taken place, it 

 is extremely unsafe to remove the balloon any 

 considerable distance, even when it is packed 

 loosely, unless steps have been taken to counter- 

 act the difficulty. There is no danger of heating 

 when the balloon is extended at full length in 

 the shade. But when it is rolled up tightly, 

 even if left in the open air, charring will surely 

 take place in a few hours. Where shipment is 

 necessary, it has been found that sprinkling the 

 balloon over with some of the lighter products 

 of petroleum, as, for instance, kerosene, or a mixt- 

 ure of this with benzine, is a sure preventive of 

 spontaneous combustion. After seasoning has 

 taken place, which may be determined by rolling 

 up tigntly and carefully observing the result, 

 the balloon may be packed away with safety. 



Rubber-coated Balloons. Balloons made 

 impermeable by India-rubber may consist of one 

 or more thicknesses of silk or cotton, and the 



