Item RPI/6/42 - Engraving fig. 299 from John Henry Pepper's The Boy's Playbook of Science

Engraving fig. 299 from John Henry Pepper's The Boy's Playbook of Science, 2nd ed., Routledge, Warne & Routledge, 1860.

Fig. 299. A. One or more lime lights, throwing rays reflected by concave mirrors on to the face B, from whence they are reflected to C C, the first condensers. D D. Object glasses. This instrument is made by Mr Collins, who has the tools for making the reflectors with correct curves. The picture of the face on the disc is covered with black spots if the reflectors are not perfect.