1-152-538 - Ann Ronan Picture Library/Heritage-Images

Steel production: a forge with bellows to produce draught, 1556. In the foreground bars are being hammered with a mechanical hammer. The power source (probably water) is out of the picture on the left, but tappets on a revolving barrel would raise the hammer for the next blow as they engaged with a trip mechanism. After hammering the bars are being slaked in water. From De re metallica by Georgius Agricola. (Basel, 1556).