"Box reflex camera obscura with 2 3/8-inch meniscus lens concavo-convex of about 11 inches focal length. A camera obscura is a box or darkened rooom with a lens or hole through which the image of an external object is projected onto the opposite inside wall. This camera obscura has rack and pinion focusing. Camera obscuras were known to the ancient Chinese and Greeks, and used by Arab astronomers in the 10th century to observe the sun. During the Renaissance, artists used camera obsucras to help them draw more accurately."
© Science Museum / Science & Society Picture Library