Bickford’s fuse is much used by miners for exploding their charges. For this purpose it is invaluable, a given length burning a given time, so that the miner knows exactly what his fuse must be in order to afford him the time necessary for escaping to a safe distance before his charge goes off. It is invaluable to you boy balloonists in another way. The prettiest balloon firework effects are those which are not lighted at the time when you let off your balloon, but which take fire apparently of themselves after the balloon has gained a considerable elevation. Bickford’s fuse enables you to accomplish this in a manner you will soon understand.
Looked at casually, Bickford’s fuse might be taken for a piece of black cord, something in size like this ([Fig. 10]). The outside is of woven material made waterproof. The middle contains an inflammable wick, burning regularly to time.
If you were to pass through a length of Bickford’s fuse transversely a thread fixed at its upper end, and having a weight attached to the other end, and if then you were to light the fuse at one end, you see what would happen. The fire would creep along until, coming to the thread, it would burn the latter, and the weight would fall. It is many years since I had occasion to work with Bickford’s fuse, so I forget its rapidity of burning. It does not signify; when you have got your fuse you can try an experiment with any convenient length, timing the rapidity of burning by a watch.
Quickmatch consists of a paper tube with a rapidly inflammable wick running through it, the intention being that flame applied to one end of the match shall flash to the other, and instantaneously. The actual fireworks I recommend you to get are some blue-lights, some Roman candles, a few Catherine wheels, crackers, and maroons. The Roman candles you will only require to pick to pieces for the sake of the stars they contain, so if you could get the stars you would not want the candles. Mr. Brock, I think, would supply you with stars of various colours. He uses small pill-boxes for holding the star material.
I have now to explain to you a few fireworks for your balloon.
Fig. 12.
1. Fixed piece of blue-lights.—Having selected a cork of suitable size, bore its circumference with as many holes not going to the middle as you design to have blue-lights. Each excavation made will receive the blank end of a blue-light, just as a candlestick receives the end of a candle, so that when finished, supposing you to have used four blue-lights, you will have made something like this ([Fig. 12]).
Fig. 13.