English: Common smiths’ bellows. A is the blast pipe, B the movable lowest board, C the fixed middle board, close to which the pipe A is inserted, and D is the movable uppermost board pressed upon by the weight shown. The board B is raised by means of a hand lever L, through either a chain or a connecting rod, and lowered by a weight.
Illustration from 1911 Encyclopædia Britannica, article Bellows and Blowing Machines
This image comes from the 13th edition of the Encyclopædia Britannica or earlier. The copyrights for that book have expired in the United States because the book was first published in the US with the publication occurring before January 1, 1929. As such, this image is in the public domain in the United States.
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