Plate V.

This may be one of the machines which Leonardo, in his letter to Sforza, refers to as "engines for discharging missiles of admirable efficacy, and hitherto unknown."
Its action seems to be as follows: The men who furnish the motive power are protected from the missiles of the enemy by the sloping barrier; the four cross-bows inside are
drawn by the operator, who causes the line attached to each bow-string to bind upon the immovable axle. At the right moment the bow is released, and sends the projectile
through the opening under the platform. The drawing at the right seems to give an Impression of the engine in the heat of action.