302 PROCEEDINGS OF THE AMERICAN ACADEMY 



ration of the dye is substantially the same as that employed by J. B. 

 B. Wellington,* and is as follows . 



Fifteen grains of cyanine are gently heated (over a steam bath) for 

 from thirty to forty minutes in combination with 1 oz. of chloral hy- 

 drate and 4 oz. of water. The whole mixture should now be stirred 

 vigorously. While this operation is going on, 120 grains of sulphate 

 of quinine are dissolved by heat in a few ounces of methylated spirit. 

 (If methylated spirit cannot be obtained, a solution of 90% alcohol 

 and 10% wood spirits will answer perfectly well.) One ounce of 

 strong aqua ammonia is now slowly added to the cyanine mixture 

 above. Violent ebullition takes place immediately, chloroform being 

 evolved, and cyanine is deposited in a soluble form on the sides of 

 the vessel. The mixture is allowed to settle for a few minutes, and 

 then the supernatant liquid is decanted off very slowly, care being 

 taken not to detach any of the cyanine that is formed on the sides. 



To the remaining cyanine, three or four ounces of methylated spirit 

 are added to dissolve the cyanine ; the quinine solution is then added ; 

 and to the whole more methylated spirit, until the whole mixture 

 measures from ei^ht to nine ounces. This solution constitutes the 

 " stock " solution, and should be kept away from all light, as it is very 

 apt to become decomposed. 



All of the above operations should be conducted in as little light as 

 possible. The following staining and drying processes should be 

 conducted in absolute darkness. 



To thirty ounces of water are added 1J drachms of the cyanine 

 stock solution ; the graduate that contained the cyanine is now 

 washed out, 1^ drachms of strong aqua ammonia are added, and the 

 whole mixture is stirred vigorously. Into this bath two or three 

 plates, or half a dozen strips, can be dipped at once. They should 

 be left there about four minutes ; meanwhile the tray containing 

 the plates should be rocked continuously, so as to insure a uniform 

 action of the dye. 



This bath, after having been used once, should be thrown away, as 

 the action on a second batch of plates would be weak and imperfect. 

 The plates can now be drained, dried, and used. While developing, 

 I was careful to exclude all light whatever, although I think it pos- 

 sible that the plates may be developed safely in a dark greenish 

 yellow light. The developer used was a pyro. and potash developer 

 of (generally) normal strength. 



* See Anthony Photographic Bulletin, December 24, 1887. 



