ON LOADING PUNT-GUNS 213 



and in each charge a varying strength is usually found. Hold 

 to the fine gunpowder ; it is most reliable. 



It should be almost unnecessary to mention that tubes, 

 caps, etc., for igniting the big gun must be kept as dry as 

 possible when afloat. Nothing beats a glass bottle tightly 

 corked in which to keep these articles. Ordinary matches 

 should likewise be kept in a similar vessel, or else, if carried 

 loose or in chip match-boxes in the pocket, they are very liable 

 to become damp, or even wet and useless. A further protection 

 against damp affecting matches is to half fill the bottle they 

 are to be kept in with bran or sawdust — the latter for preference. 

 A leathern cover should be strapped around the breech of all 

 punt-guns, so as to protect this part of the gun from wet. 



We intended to give full details of an electrical ignition for 

 punt-guns, so that this method might be employed aboard 

 motor-propelled craft. But we have conclusively proved by 

 experiment that there is no advantage whatever to be gained 

 by using an electric spark for this purpose, even where all the 

 apparatus is at hand. We much prefer percussion ignition, 

 for reasons too numerous to mention here. We have, however, 

 made lengthy experiments on this subject, and can say we 

 attained equally good results as with the customary methods 

 of ignition, yet no better, and we must add, with not half the 

 confidence in the result. The chief drawback is the insulating 

 qualities of the priming powder in the firing cartridge or tube, 

 offering a high resistance against the spark. Our tests were 

 made entirely with B.L. guns. Ordinary induction or sparking 

 coils similar to those used on motor-cars are almost useless for 

 firing gunpowder, as the resistance of the powder against a 

 spark appears to be many times greater than explosive gases, 

 even under compression. At least two 4-volt accumulators 

 coupled up in series are necessary for the primary circuit of the 

 coil. The electrical potential difference at the point of sparking 

 must be of very high voltage to strike through the powder 



