Model of a Fan; Model of a fan operating as a double bellows. Part of the cover can be removed to show the inside. In the body; which has the shape of a circle segment at its point; a plank moves back and forth; hinged at the point. The board is pulled with ropes on either side. Simple valves consisting of a wooden flap covered with chamois leather let the air in in turns. When the air is compressed on one side; it is discharged via a similar valve at the top to a round ventilation duct; one of which is mounted on each side.; anonymous; Netherlands; c. 1740 - c. 1800; wood (plant material); brass (alloy); chamois (animal material); rope; h 27 cm x w 35.9 cm x d 12.8 cm