Of foremost notice is Swift's invention of the electric rifle, a gun which fires bolts of electricity. The electric rifle can be calibrated to different levels of range, intensity and lethality; it can shoot through solid walls without leaving a hole, and is powerful enough to kill a rampaging whale, as in their steamer trek to Africa. With the electric rifle, Tom and friends bring down elephants, rhinoceroses, and buffalo, and save their lives several times in pitched battle with the red pygmies. It also can discharge a globe of light that was described as being able to maintain itself, like ball lightning, making hunting at night much safer in the dark of Africa. In appearance, the rifle looked very much like contemporary conventional rifles.