painter's Camera Obscura in the Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers of 1772

longitudinal section of camera obscura from Meyers Großes Konversations-Lexikon, 1905

The Camera Obscura (literally, dark or hidden room, from Latin) is a device consisting of a room or box which is enclosed except for a small hole; this means that the room is kept dark but for the light coming in through the hole. This light projects an image of the outside scene onto a wall or screen. An improvement is to mount a lens in the hole. Artists have used camera obscurae as an aid; the projected image can be drawn around to obtain a picture in correct scale and perspective.

painter's Camera Obscura in the Lexikon der gesamten Technik ca. 1910