f – n – S – m. Very swift motion, which in a given time will have made one braccio of movement for every hundred. That is, if you move n as far as m, f will descend to the low point S. And if such an instrument were continued at length beyond f, that length too would make its whole movement in precisely the same time.

This one below is an easy motion, because the wheel and its pinion are made as a screw, although the pinion would suffice merely to be toothed. There is no other advantage, except that the screw is more durable, because its contact is of greater width.

furnace floor – c b a – m n – e d – p o – r q – g f – h. a c d e are dampers that send air beneath the wood kindled above the holes o p; b is where the wood is put in; the opening n m is where the smoke goes out; the mouths o p are where the fire enters, whirled together with the air; q r is where the furnace fire escapes; f g is where one looks into the furnace and where the bronze is put in; h is where that bronze comes out.

b a – S r – o c. Here a b is where the flame enters the furnace; the 5 mouths are where that fire leaves the furnace; r S is where the furnace is charged with bronze.

m – n. Let the internal diameter of the furnace m be 2 and 5/8 braccia, and the window n, where the flame enters, is 7/8 high and 5/8 wide, and its top adjoins the vault of the furnace; and the windows where the flames come out are square and are 6/14 on each side, and the mouths where the wood is put in are square, half a braccio. The bottom of the furnace should slope one and a half once at the middle of its width, and toward the spine it should slope 2 and 1/2 once; and the thickness of the furnace at the foot, at the springing of the vault up to half a braccio above it, must be one and a quarter braccia, and from there upward let it be half a braccio thick.