P EOTOGRAPHICAL SECTION PROCEEDINGS. 1009 



November 10th, 1868. 



Mr. Henry T. Anthony in the chair. Mr. Oscar G. Mason, Secretary. 



The cliairman introduced Mr. Thomas Garfield, of Boston, Mass., 

 who gave a very interesting account of his researches on the effects 

 of sunlight on glass, during the last five years. His remarks were 

 very fully illustrated by specimens of glass used in his experiments, 

 and a great number of most carefully finished photographic impres- 

 sions obtained by the exposure of sensitized paper under such 

 specimens, so arranged as to plainly show the changes produced by 

 sunlight. In some samples of glass exhibited, the change produced 

 by an exposure to sunlight during only one day was quite perceptible ; 

 others showing the^ effects of months and years of similar exposure. 

 Some samples exhibited had been exposed for a period of seventy -five 

 years. 



With one or two exceptions only, Mr, Garfield had found that all 

 kinds of glass are, more or less, effected by exposure to direct sun- 

 light. He found that the great majority had a tendency to change 

 toward the non-actinic shades of green and yellow, while some samples 

 were much inclined to violet and purple. His experiments had, in 

 the main, been confined to plate and sheet window glass. The few 

 samples of optical glass used had exhibited quite a similar tendency 

 to change. His systematic and carefully recorded, observations 

 elicited the praise of all present. 



Mr. A. J. Drummond exhibited a series of twelve prints on Swan's 

 pigmented tissue, illustrating his method of working the same, and 

 the various tones which could be produced by the carbon process. 



Mr. Kurtz exhibited further samples of the beautiful results which 

 he obtains by a careful, artistic use of light in his studio. 



The section then adjourned to the first Tuesday in December. 



December 1st, 1868. 



Vice-President Joy in the chair. Oscar G. Mabon, Secretary. 



Mr. C. "W. Hull exhibited a number of mezzotint photographs by 

 Carl Mienerth, of Newburyport, Massachusetts, which called forth a 

 general discussion upon the use of the same or similar devices for the 

 production of like efiects. One firm had sent samples of such work 

 from Philadelphia to Europe several years ago. 



