II 
and not depending on gravity. 3. The luminous spot on the 
positive carbon obscured from the condenser and the crater 
on the negative carbon presented in the most favorable way 
by tilting the carbons thirty degrees. 4. Adjustment of the 
light to the optical centre of the lens automatically. 5. Con- 
venience of adaptation to polariscope and other apparatus. 
Made by J-B: Colt & Co. 
52. ELECTRIC PROJECTION LANTERN as used by the American 
Museum of Natural History. Advantages claimed: 1. Steadi- 
ness of light. 2. Simplicity of the mechanism of the lamp, 
which is provided with every possible adjustment. 3. Ability 
to change the illuminating power from 700 to 2,000 candle- 
power without causing light to flicker. 4. Adjustment of the 
carbons to optical centre of the lens automatically. Made by 
Charles Beseler. 
53. EXAMPLES OF VOGEL-KURTZ COLOR PRINTING, by the use 
of three negatives and three primary colors, red, yellow and 
blue. This process is described in Wilson’s Photographic 
Magazine for April, 1893. 
54. EXAMPLES OF COLOR PRINTING by the process employed 
by Mr. Edward Bierstadt. 
55. SERIES OF LANTERN SLIDES showing a novel method of 
illustrating botanical subjects, as devised and used by Mr. 
Van Brunt. 
56. THE WILLIAMS FLASH MACHINE, for replacing daylight 
by artificial light and for obtaining photographs instantane- 
ously in a manner equal and in some respects superior to 
the use of daylight. By the simple pressure on a pneumatic 
bulb a space of 36 square feet is illuminated with a very 
actinic violet flame, the camera shutter being at the same 
moment released. 
57. SERIES OF PORTRAITS 25x30 inches made with above- 
described apparatus and demonstrating the advantage of having 
an illuminating source directly controllable by the operator 
58. DALLMEYER TELE-PHOTOGRAPHIC LENSES. These com- 
bine the principles of the telescope and the photographic lens, 
