128 ELEMENTARY PHOTO -MICROGRAPHY. 



Citric acid . . . . . . 3 grains 



Water . . . . . . ij ounces. 



Equal parts of A and B. 

 After toning, clear by rinsing in dilute solu- 

 tion of carbonate of soda. Wash and dry. 

 Sepia. 



A. 

 Uranium nitrate . . . . 2 grains. 



Acetic acid . . . . 18 drops. 



Water . . . . . . i ounce. 



B. 

 Potass, ferricyanide . . 3 grains. 



Acetic acid 18 drops. 



Water . . . . . . i ounce. 



Equal parts of A and B. Wash and clear in 

 weak acetic acid bath. Wash again in clean water 



and dry. 



Brown. 



Bleach with mercuric chloride. Wash and 

 immerse in 20% solution of hypo. 

 Thoroughly wash and then dry. 



Blue. 



Bleach in 10% solution potass, ferricyanide. 

 Wash ten minutes, then immerse in 5% solution 

 of ferric chloride. Wash and dry. 



Green. 



The slide may be stained with aniline dye 

 when it is not necessary to preserve high lights, 

 or the following bath can be tried : 



