Proceedings of the Photographic al Section. 1069 



ago, and detailed to the pliotograpliical society. The collodion used 

 in the production of the negative exhibited, was exposed to "bright 

 sunlight one day, and to diffused light several days, and then kept 

 in the dark a few hours before use. 



Professor Tillman remarked that the negative was a good illustra- 

 tion of the mechanical theory advocated by Mr, Oory Lee, of Phila- 

 delphia. 



Mr. Boyle exhibited and explained the practical advantages of Iiis 

 double field comet seeker, which is so constructed as to enable the 

 observer to examine twice the amount of space seen in the ordinary 

 instrument of the same aperture. Mr. Boyle also exhibited and 

 explained his model of the moon, which he had recently finished. 



The Secretary distributed to members, samples of albumen papei;, 

 which was manufactured in Europe, and received from Mr. Willy 

 Wabach, the importer and agent for its sale, at 43 John street, jS"ew 

 York. 



Mr. Hill exhibited a print by Herr Colbert's process, which was 

 discussed at the last meeting of the Section. 



Mr. T. S. Keed suggested the use of carbolic acid in the printing 

 bath ; he had added two drops to each oupce of his solution, and 

 found it improved its working quality. 



The Section then adjourned to the first Tuesday in June. 



une 1, 1869. 



Professor Chajrlk8 A, Jov, Vice-President, in the chair ; Mr. O. G. Masox, 

 Secretary. 



Mr. IsTewton and Mr. Mason gave verbal reports of the progress 

 made by the committee appointed by the Section to investigate the 

 properties and working advantages of the Alcaline silver })ath, 

 recommended by Mr. McLochlin, of England. As some importance 

 had been attached to the peculiarity of the nitroli of silver crystals, 

 described by Mr. McLochlin, the conmiittee had decided to experi- 

 ment with solutions of crystallized nitroli which had been variously 

 treated, and with crystals found under diflerent conditions, as well 

 as with fused nitroli. 



The Chairman remarked that if the heat was raised above a certain 

 point, say to a dull red heat, nitrate acid would be formed, changing 

 a part of the nitrate, to nitrite of silver. 



Mr. S. P. Eeed stated that he had found a very remarkable improve- 



