122 THE MICROSCOPE. Aug. 



precipitate at first thrown down is just dissolved, no 

 more. Be very careful in adding ammonia so as not to 

 add too much ; but in order to guard against an ex- 

 cess of ammonia, add a crystal of nitrate of silver and 

 shake ; if the solution becomes turbid it is all right ; but 

 if it clears up, more silver should be added until it re- 

 mains permanently turbid. Then filter solution through 

 a double paper filter, pouring back until it comes through 

 clear; add distilled water through filter to make 12 oz.; 

 place in clean bottle and add 1 oz. alcohol. Shake thor- 

 oughly and cork, place in cool dark place for 5 or 6 



hours. 



Solution No. 2. 



Nitrate silver, ... . 16 grains. 



Rochelle salts, ... . . 12 grains. 



Distilled water, . . . . 12 oz. 



Alcohol, . . . . . 1 oz. 



Place the salts and 8 oz. water in a clean porcelain or 

 porcelain lined evaporating dish, place over heat and 

 raise to gentle boil. When boiling add the silver pre- 

 viously dissolved in 1 oz. distilled water and stir with 

 clean glass rod. Continue to boil gently until solution, 

 which usually turns brown then black, turns gray; then 

 continue to boil for a minute or two more ; add balance 

 of water and filter through paper ; make up to 12 ounces 

 with distilled water and add alcohol. Place in clean 

 bottle, cork tightly and keep for five or six hours in cool 



dark place. 



Solution No. 3. 

 Cyanide mercury, ^ ... 16 grains. 



Cyanide potash, .... 8 grains. 



Water, . . . . . . 2 oz. 



Mix. Fiat sol., ..... 



This solution is used only for amalgamating purposes 

 and is very poisonous. It has no part in silvering but 

 by displacing a certain portion of the silver with mer- 

 cury forms an amalgam that is lighter and more adher- 

 ent to glass then the silver itself. This it does instantly 



