78 



the cupric sulphate solution as given above. Solution 2 is the 

 alkaline tartrate solution also given above. Solution 3, the potas- 

 sium ferro-thiocyanate solution is as follows: 



Potassium ferrocyanide, 15 grams 



Potassium thiocyanate, 62.5 grams 



Anhydrous sodium carbonate, 50 grams 



Water up to 500 cc. 



In testing use equal volumes of the solutions. 



Cochineal Solution. Boil 40 grams of cochineal in 800 cc. 

 of water. When cool add 200 cc. of alcohol and filter. 



Decinormal Oxalic Solution. Dissolve 6.285 grams of pure 

 oxalic acid in enough distilled water to make at or near 15° C. 

 (59° F.), exactly 1000 cc. 



Decinormal Sodium Hydroxide Solution. Dissolve 3.996 

 grams of pure sodium hydroxide in enough distilled water to 

 make, at or near 15° C. (59° F.), exactly 1000 cc. 



Ehrlich's Diazo-reaction. 



Solution 1. Sulphanilic acid, 2 grams 



Hydrochloric acid, 50 cc. 



Distilled water, ^ 1000 cc. 



Solution 2. A 0.5% solution of sodium nitrite. Use in the 

 proportion of 1 part of No. 2 to 50 parts of No. 1. 



Esbach's Reagent. 



Picric acid, 10 grams 



Citric acid, 20 grams 



Distilled water up to 1000 cc. 



Fehling's Solution. 



Solution A. Pure Copper Sulphate crystalline, 34.64 grams- 

 Distilled water up to 500. cc. 



Solution B. Sodio-potassium tartrate (Rochelle 



salt), 173. grams 



Pure caustic potash, 125. grams 



Distilled water up to 500. cc. 



Use equal parts of A and B. 



