branch of study: optics
inventor: William Hyde Wollaston, 1806
The Camera Lucida, sometimes known as Wollaston prism, consists of an upright brass column, to which a prism holder is mounted. By looking through the prism you can see a sheet of paper on the table in front of you and superimposed an image of an object which you want to sketch on the paper.
The Camera Lucida facilitates to make a drawing of a microscopic object (using a suitable objective lens!) or of a macroscopic object.