History
The first blasting cap or detonator was demonstrated in 1745, when a Dr. Watson of the Royal Society showed that the electric spark of a Leyden jar could ignite black powder.
In 1750, Benjamin Franklin in Philadelphia made a commercial blasting cap consisting of a paper tube full of black powder, with wires leading in both sides and wadding sealing up the ends. The two wires came close but did not touch, so a large electric spark discharge between the two wires would fire the cap.
In 1822 the first hot wire detonator was produced by Dr Robert Hare. Using one strand separated out of a multistrand wire as the hot bridgewire, this blasting cap ignited a pyrotechnic mixture (believed to be potassium chlorate/arsenic/sulphur) and then a charge of tamped black powder.
In 1863 Alfred Nobel introduced the first Pyrotechnic Fuse blasting cap, using mercury fulminate to detonate nitroglycerin.
In 1868, H. Julius Smith introduced a cap that combined a spark gap ignitor and mercury fulminate, the first electric cap able to detonate dynamite.
In 1875, Perry "Pell" Gardiner and Smith independently developed and marketed caps which combined the hot wire detonator with mercury fulminate explosive. These were the first generally modern type blasting caps. Modern caps use different explosives and separate primary and secondary explosive charges, but are generally very similar to the Gardiner and Smith caps.
Electric match caps were developed in the early 1900s in Germany, and spread to the US in the 1950s when ICI International purchased Atlas Powder Co. These match caps have become the predominant world standard cap type.
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