A way of spreading the dharma is just telling people, sharing with them your experiences. Never push it, never be a missionary. Be completely selfless; realize you're only an instrument of eternity.
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.