Bombard powder, the line of motion, and loaded arcs
Notes on gunpowder burning, the speed of moving bodies, and a power loading paired semicircular arcs
A sheet of physics jottings surrounded by small mechanical and geometric sketches. Leonardo argues that a bombard packed solid with powder will expel much of it unburnt, states that every heavy body weighs along the line of its motion, and defines the swifter mover as the one that covers more distance in equal time. A lettered pair of semicircular arcs (b c d e) illustrates that a single power able to load one arc can load many joined together, while a large compass-drawn circle construction fills the lower left. Further faint sketches and numerals not transcribed here are also present on the leaf.
On this page
A bombard barrel filled solid with powder
If the whole barrel of a bombard is packed with powder alone, Leonardo reasons that once the charge is kindled enough to fill the barrel with fire, the remainder of the powder is driven out still unburnt. The observation treats the combustion and expulsion of the charge inside the gun.
Weight along the line of motion; the swifter mover
A short axiom states that every heavy body weighs along the line of its own motion. A companion note on the left defines the swifter of two moving bodies as the one that, in an equal span of time, accomplishes more movement.
Paired semicircular arcs b c d e loaded by one power
Two semicircular arcs are lettered b c d e. Leonardo notes that c naturally travels to b in one unit of time while e does the like toward d, and that with the heads of the two arcs joined a single power that loads one arc can load many together.
Circle construction in the lower left
A large compass-drawn circle enclosing inscribed lines and lens-shaped figures occupies the lower-left quarter of the sheet. It is a geometric construction rather than an illustration of the physics notes, and its lettering is not transcribed in the bundle.