Gatling guns

Richard Gatling hoped the gun bearing his name would reduce war casualties:

It occurred to me that if I could invent a machine - a gun - which could by its rapidity of fire, enable one man to do as much battle duty as a hundred, that it would, to a large extent supersede the necessity of large armies, and consequently, exposure to battle and disease [would] be greatly diminished.

The gatling gun was eventually declared obsolete, later revived as a powerful tool of death and destruction Gatling could not have imagined.