The exploder similar to the one pictured was first patented by H. Julius Smith, and produced and marketed by the Laflin & Rand Powder Company. It was known as the Magneto No.3. In 1905, DuPont purchased the company and took over production of the exploder.

The artifact is interesting and ingenious on its own though historical context gives it significance. In the early days of hardrock mining in the American West, black powder was the explosive used. It is a mixture of sulfur, saltpeter (potassium nitrate), and charcoal, and the ratio of these three determines the explosive characteristics -- blasting powder has less saltpeter and more sulfur than gunpowder.

Then came nitroglycerin, which was first used in the American West by the Central Pacific Railroad in the Sierra passes. It is five times as powerful as black powder and was much better at pulling rock, but it is very unstable. It was very dangerous to manufacture and to handle and its danger made it less attractive to miners than black powder.

It was not until after 1867, when Alfred Nobel received patents for dynamite and blasting caps that black powder lost its primacy. Nobel found that a chalky earth, kieselguhr, would absorb a great deal of the highly unstable nitroglycerin. This mixture was packed into cylinders made of waxed paper or later plastics. These cylinders called cartridges, were very stable and required a shock rather than a flame to set them off, and it was the blasting cap that provided the shock.

These metal or plastic cylinders generally contained fulminate of mercury due to cost and stability, and they were set off by fuse-and-caps or by electric blasting caps. (It needs to be mentioned that old blasting caps can occasionally still be found in mining and construction areas. They are extremely dangerous and should not be touched. Report any old caps immediately to the local police department).

Since the electric blasting cap was considered safer, quicker, more efficient, more certain and cheaper, they came into wide spread use. It is was the exploder that played an integral part in making this possible.

Terry Girouard,
Previous Curator of Collections