1072 Transactions of the American Institute. 

 November 2, 1869. 



Prof. S. D. TiLLMAX in the chair ; Mr. O. 6. Mason, Secretary. 



Mr, IS'ewton, Chairman of the Connnittee on McLocklin's Negative 

 Bath, gave a verbal report of his experiments in Qxposure of silver 

 crystals to snnlight since the last meeting of the Section. He had 

 been able to make a first class negative by sensitizing in a plaiti 

 alkaline solution of sunned crystals of nitrate' of silver witliout 

 iodizing. 



Prof. Tillman remarked that the interesting fact of a plain solu- 

 tion being strongly alkaline by merely exposure to sun liglit, as stated 

 by Mr. Newton, deserved to be followed up by further investigation. 



Mr. Mason gave a description of several experiments which h© 

 had made in exposing silver crystals and solutions to sunlight dur- 

 ing the summer in furtherance of work before the committee. He 

 had exposed crystals to sunlight- after having carefully sealed them 

 tip in bottles, from which the air and all moisture had been expelled-, 

 and into which he had introduced glass tubes containing various 

 alkaline reagents. 



Mr. Newton exhibited several very fine negatives made by the 

 tea process, as detailed by him at a previous meeting of the section. 

 He also exhibited a collection of unmounted prints from tea plateB 

 five by eight inches, which gave evidence that the process was 

 adapted to first class work when properly manipulated. 



Mr. Kurtz exhibited two eight by teu negatives, and prints from 

 the same, saying that one of his reasons for presenting them before 

 the Section was for the purpose of demonstrating the fact that all his 

 best results were not produced from retouched negatives, as he under- 

 stood that many believed, and several had stated such to be tlie case. 



Tlie negatives and prints were admired and highly spoken of by 

 those present, and led to considerable discussion upon the claims of 

 photography and photographers among the arts and artists. 



Mr. Boyle exhibited drawings and described liis large refracting 

 stereoscope, which consists of two achromatic prisms for eye pieces, 

 which sliould be of sufficient power to refract two rays of liglit Avliich 

 would diverge from the observer into a direction which Avould converge 

 as their distance from the observer increased, and intersect each other 

 at about the distance of tv/enty inches from the eyes. The centers of 

 the two pictures viewed will coincide at this jjoint and form one pic- 

 ture, and as the original position of the pictures before refraction by 



