Figs. 10., 11., 12., 13., 14., 15., 16., 17., 18., 19., and 20.
Lamp cotton is the best material for the wick, though any of the other substances already mentioned may be used if this is not come-at-able. It may be saturated with methylated spirit, or, if the material is easily accessible, melted tallow. In the latter case the wick should then be sprinkled with turpentine that it may catch fire readily. The tallow gives the best light, and lasts the longest.
Two pieces of thin wire should be attached to the hoop as shown in Fig. 7, W W, and your ball of lamp-wick is to be placed in the centre, L W. The placing of the wick is the last operation, but of course, it will have been prepared beforehand. It is simply a loosely rolled ball of lamp-cotton through which a piece of fine wire has been passed and the ends formed into hooks (Fig. 8). The size of the ball must be governed by the dimensions of the balloon and by your ambition as to the height to which it is to rise. The wick may easily be made large enough to carry the balloon out of sight altogether, especially if tallow be used.
In this case the wick should have been saturated with melted tallow beforehand, but where methylated spirit is used the proceedings must be delayed till the moment of ascension.
With a fan—a folded newspaper will do as well as anything—fan the balloon full of air to start with. Then your assistant must elevate the balloon to the right height by the aid of a smooth stick inserted in the loop, and he must stand on something to raise him to the right level.
Now the air in the inflated balloon must be warmed by holding beneath it a paper torch, care being taken that no flame touches the balloon, or it will be shrivelled up by the fire in a moment and your labour wasted.
Another assistant meanwhile should have been looking after the methylated spirit—if you use the tallow you can do without him. The spirit should be kept in a closely corked bottle and as far from your paper torch as possible. When the balloon begins to try to rise give the word to assistant No. 2, who will pour some of the spirit into the jam-pot in which the wick is lying, wait till it is saturated, and then, taking it from the jam-pot, run with it to the balloon and attach it to the cross wire by the hooks. Directly it is in position, give the word to assistant No. 1 to let go; touch the wick with a light, and up will sail the balloon into the air. A windy day should, naturally, be avoided, or your balloon is not likely to proceed far on its journey in safety.
But a good deal more is to be got out of a fire balloon than a mere ascension, and even the mere ascension may be improved. You may, for instance, attach a car to the balloon (Fig. 9) and a couple of figures A A—it matters little how rough they are—will, very shortly after the liberation of the balloon, look so natural that the balloon will be taken for the real thing. When it has mounted but a little distance there is nothing by which its size may be compared, and if netting is imitated by lines drawn with a pen and ink, the illusion will be yet more complete.
The car may be made of a square of writing paper with the four edges folded over equally all round. The corners should then be pinched together, folded over as in the illustration, and secured with a little paste.