Photo GRAPHICAL Section Proceedings. 1025 



PROCEEDINGS 



June 10, 1867. 

 Lewis M. Eutherfurd, Esq., President, in the chair; 0. G. Mason, Secretary. 



After remarks by Prof. Tillman and others, upon the action of 

 the American Photographical Society, and the Institute, resulting v 

 in the formation of the Section, the regular order of business was 

 proceeded with. 



Mr. Hull read a communication from Mr. W. H. Christian, of 

 Richmond, Vermont, asking for information regarding unusual 

 chemical effects on the surface of albumen paper. Mr. Hull also 

 exhibited a camera with speculum reflector, as constructed for 

 making unreversed daguerreotypes in the early days of the art. 



Mr. Chapman read a paper upon the preparation of dry plates 

 without the use of a sensitizing bath, by introducing bromide of 

 silver into the collodion, and exhibited prints illustrating the work- 

 ing of the process, Avhich he considered about five times as sensi- 

 tive as the ordinary tannin process. He also exhibited a camera 

 so constructed as to more effectually equalize the action of light 

 in landscape photography, by vignetting the sky or giving the 

 light portions less time of exposure. 



Mr. Hull detailed "a process described to him by Mr. Martin, of 

 Albany, who first coats his plates as for tannin, then dips in a 

 bath of acetate of morphine, one grain to the ounce, and develops 

 with Gelat's iron developer. 



Mr. Rutherford called attention to an error in the Philaddpfiia 

 Pholographer, regarding an article by him published in Silliman^s 

 Journal. He also called attention to and explained an error in the 

 same journal and the British Journal of Photography, regarding 

 the theoiy of correcting two meniscus lenses by the distance of 

 separation or radii. 



Prof. Vanderweyde exhibited photographs made by a single non- ^ 

 achromatic lens, and detailed experiments which he had made with 

 such lenses before the introduction of the daguerreotype. After 

 remarks upon the theory of distortion, in the images made hy such 

 lenses, he exhibited photographs made by a single achromatic and 

 by an achromatic meniscus. 



Mr. Mason exhibited a negative of an electric discharge during 

 the severe thunder-storm on the night of May 11th. The image 

 aNST.l 65 



