do it with some drawings of them on which I am working every day."
This list, even without the drawings, was startling enough, even though (as has been pointed out) 10 the inventions were applications of known mechanical laws to ideas which other people of the time had already had. They still bear witness to his mechanical genius and also tell something more definite about what he had been studying than the letters had revealed.
1. The construction of a ship which, with its one-man crew, could go under the sea, in any desired direction, and could inflict much injury on enemy ships.
2. A novel construction of a siphon, whereby water can be driven from a river to higher places, in great abundance and in a short time.
3. On the lifting of weights by means of water and this portable siphon, more easily than by mechanical forces.
4. On constructions [locks] even in places where there is no flow of water, whereby a whole ship with its cargo can be raised to a given height in one or two hours.
5. A machine vivified by means of fire for throwing out water; and the way of constructing such machines at smelting works where there is no fall of water, but the water is still. The fire and the forge should be able to supply enough water for the wheels.
6. A drawbridge which can be closed and opened from within the gates and walls.
7. New machines for condensing and exhausting air by means of water; and concerning a new air pump worked by water and mercury without any siphon, which works better and easier than the ordinary pump.
I have also other new plans for pumps.
8. A new construction of air guns, a thousand of which can be exploded by means of one siphon and at the same time.
9. A universal musical instrument whereby the most inexperienced player can produce all kinds of melodies, these being found marked on paper and in notes.
10. A universal sciagraphia [art of making shadows as for sundials] or a mechanical method of delineating hours of every kind and on any surface by means of fire.
11. A water clock with water as the indicator which, by its flow, shows all the movable bodies in the heavens, and produces other ingenious effects.
