How to aim a swivel-gun true with two sights
Method for setting sights e and d so near sight, far sight and the ball's mark form one line
The sheet is built around a long practical text on aiming a spingarda, a light swivel-gun, whose two sights are lettered e and d. Leonardo instructs the gunner to fire a trial shot, mark where the ball strikes, then adjust two sights without moving the piece until the near sight, the far sight and the mark all fall in one straight line, cutting that alignment permanently with a chisel. A carriage is labelled within the gun's drawing, and a top note begins a separate memorandum on making a great light.
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Sighting the swivel-gun with sights e and d
Fix the piece and fire one trial shot at a wall or door so the ball leaves a mark; then, without moving the gun, shift two sights until the foot sight, the head sight and that mark lie in a single straight line, and cut the alignment with a chisel. Thereafter you will always shoot straight by bringing the two sights and the target into one line. The two sights are lettered e and d.
The carriage of the swivel-gun
Within the drawing of the spingarda a component is simply labelled as the carriage. It supports the barrel and the sighting arrangement described in the main text.
Memorandum on making a great light
An unfinished note at the top, beneath an indeterminate sketch, begins an instruction on how to make a great light. The entry breaks off before the method is given.