 The first blasting cap or detonator was demonstrated in 1745 when British physician and apothecary William Watson, F.R.S., showed that the electric spark of a friction machine could ignite black powder, by way of igniting a flammable substance mixed in with the 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.