SCIOPTICON MANUAL. 51 



Some idea of the value of photography, associated 

 with the magic lantern, as an educational instrument, 

 may be gathered from the fact that as the camera has 

 now penetrated to almost every habitable part of the 

 globe, the physical peculiarities of every country, to- 

 gether with lifelike portraits of their inhabitants, and 

 the form and arrangement of their dwellings, may be 

 obtained in miniature, and reproduced as large as life. 



Photographs of the sun and moon in various phases, 

 and partially and totally eclipsed, also the fixed stars 

 and nebulae, have been obtained and employed for lecture 

 illustrations. Enlarged photographs of microscopic ob- 

 jects have also been obtained, and these again still further 

 enlarged to 8 or 10 feet in diameter, so that, in fact, a 

 diatom no larger than a grain of sand may be shown 

 of such a size in the lecture-room that a large audience 

 may together examine its details with perfect comfort. 

 The productions of the most celebrated painters and 

 sculptors may be shown with equal facility, as well as 

 maps, hymns, music, &c., so that an entire school may 

 learn or sing together. 



THE STANDARD SIZE FOR LAXTJBRX SLIDES. 



The ordinary wooden frame for the lantern picture is 

 7 inches long, 4 inches wide, and f of an inch thick, 

 with a circular opening of 3J inches to admit the picture- 

 glass and its protecting glass cover, and 3 inches in the 

 clear. Pictures 3i inches square are also mounted in 

 frames of the same size, leaving 3 inches square in the 

 clear. Pictures 3i inches square, with their protecting 

 glass covers, are also bound with narrow binding, and 

 may be slid along into place in the grooves of a station- 

 ary frame, so as to show 3 inches square. 



