The Microscope. 375 



NEV/S • TRp/A- 

 THE VVORKEI^S' 



The new " color photography." — (Process patented by F. 

 E. Ives, July 22d, 1890.) The process consists in first making 

 three photographs to represent the effect of the object photo- 

 graphed upon the three fundamental color-sensations (in accord- 

 ance with the theory of color-vision now accepted by all scient- 

 ists), and then combining these photographs by superposition, 

 either by projection with a triple magic lantern, or in trans- 

 parent gelatine prints. The three negatives are made from the 

 same point of view, and by simultaneous and equal exposure 

 on a single sensitive plate, the operation involving no more 

 trouble or expense than the pi'oduction of an ordinary negative. 

 The lantern positives are made in the ordinary way, and pro- 

 jected with a single source of light, in an ordinary magic lan- 

 tern, by simply replacing the ordinary projecting lens with a 

 special front, so that the color-photographs can be interspersed 

 among ordinary lantern pictures without causing any delays. 



Composite heliochromy may be said to have grown out of a 

 suggestion made by Henry Collin, Queen Victoria's painting- 

 master, in 1865, and afterward improved upon and carried out 

 imperfectly by Ducos Duhauron and others, but made successful 

 only by Ives' discovery and application ©f a new principle, 

 and rendered easy and commercially practicable by his inven- 

 tion of special optical devices. A history of the subject and 

 detailed explanation of the process was published in the Journal 

 of the Franklin Institute^ January, 1891. 



In view of the results now shown, Mr. Ives submits the propo- 

 sition that photography is no longer subject to the reproach 

 that it is incapable of reproducing the natural colors. 



Trout parasite op the Yellowstone park.* — The lake trout 

 in Yellowstone Park are infested with worms, concerning which 



* Editorial note, N. Y. Med. Journ. 



