Richard Gatling believed that his rapid-fire gun would be a boon to mankind.
A quote from a review of the book on the right by Jonathan Yardley in the WaPo:
'It occurred to me,' he wrote to a friend in 1877, 'that if I could invent a machine -- a gun -- which could by rapidity of fire, enable one man to do as much battle duty as a hundred, that it would, to a great extent, supersede the necessity of large armies, and consequently, exposure to battle and disease be greatly diminished.' As disingenuous and self-serving as that sentiment sounds, it ended up being quite correct: Innovations in arms steadily reduced the relative lethality of battles (not to mention the cost of waging war) throughout the twentieth century."