Spring-and-pawl release mechanism, with a flame recipe
A lever raised by a steel spring and held by a pawl on a toothed wheel, plus a note on coloured flames
The page works out a spring-driven releasing mechanism: a lever that turns the teeth of a wheel is raised by a steel spring, held and freed by a pawl, with an alternative lead spring and details of the catches and pins. Leonardo annotates the parts by letter — the lever at b, the spring at S, and the return piece at F — and adds that either of the two variants shown below is good. A separate opening note is a recipe: boiling linseed oil so it catches fire and throwing red wine on it raises great many-coloured flames that last as long as the wine. Much of the surrounding mirror-script is faint.
On this page
Raising the lever that turns the wheel teeth (b)
The main figure shows how to raise the lever high; the part marked above with a b is the lever that turns the teeth of the wheel. A small figure below shows the pawl (nottola) in the position it must keep.
Steel spring and the release at S
One figure is marked S: this is what makes the mechanism release. The steel spring at S is the part that pushes the lever upward; a variant at left uses a lead spring instead.
Catches, pins and the return piece F
The lever wants its catches downward, standing off from or above the pawl by about a twelfth of a finger, and the pawl must win the race as the lever falls. The pins are to be thick and durable; the piece at F is the one that returns downward empty, bringing the pawl back to its fixed seat.