Hercules brand dynamite blaster. Early 20th Century. Before the advent of tunnel boring and modern construction equipment, drilling and blasting was the only economical way of excavating long tunnels or holes through hard rock, where digging is not possible. Permits for dynamite blasting can be found in the Vernon L. Thompson Papers.
The box has a plunger mechanism with a turned-wood handle. Two brass binding screws with wing-nuts are located on the top rear corners of the box.
Inside the box, the plunger activates a rack-and-pinion gear which drives a commutator. Two electro-magnetic coils hold the charge until a spring-loaded switch at the bottom of the box is tripped by the plunger at the end of its run.
|Dimensions||H-12 W-6.5 L-8 inches|