Record. xix 



part of the gown in sunshine showed white as a positive. The 

 penumbra between light and shadow was darker. All the 

 details were sharp, but lights and shadows were somewhat 

 incongruous. With an exposure of 4800 the details had not 

 yet all reversed, but the greater part of the plate had become 

 a positive. 



The greatest exposure giving a negative which would yield 

 an acceptable print was 210, which was 39,000 times the least 

 exposure which would give a good negative. All exposures 

 of 210 and over gave complete positives when the plates were 

 developed 1.41 meter from a 16 candle lamp, or in stronger 

 light. As good a picture as has been obtained had an expo- 

 sure of 4800, and was developed within half a meter of a 300' 

 candle lamp. A fair picture had even been obtained from a 

 two-hour exposure to direct sunlight with a Cramer " Crown ' 

 plate. 



It was stated that hypo in the developing bath did not 

 affect the zero condition, or change the character as to posi- 

 tive and negative. When no hypo is used, the plate fogs so 

 quickly that the picture is invisible, before it has time to fully 

 develop. After fixing, the thin shadowy picture showing on 

 the fogged plate has the same local positive and negative 

 characters that are shown on the clearly defined picture of 

 the same exposure, when developed in the hypo-hydrochinon 

 bath. 



The greatest exposures giving good results that have been 

 measured with reasonable accuracy were about 900,000 times 

 as great as the least exposure giving a good negative in the 

 dark-room. This factor can certainly be trebled. A plate 

 having any intermediate exposure can be developed either as 

 a good positive in the light, or as a good negative in the dark- 

 room. 



It was stated that the best results with plates near the zero 

 condition had been reached with a rather strong bath, with 

 two drops of saturated hypo to the ounce of bath. 



Messrs. W. G. Chappell and Sherman Leavitt, of St. Louis, 

 and Mr. Ernest Howard Favor, of Columbia, Missouri, were 

 elected to active membership. 



Four persons were proposed for active membership. 



