l8o AGRICULTURAL ANALYSIS 



a method should be not only reasonably accurate, but also simple 

 and rapid. It is evident, therefore, that the general principles 

 already indicated must underlie any method which would prove 

 useful in factory work. The final determination by the technical 

 chemist for the purpose of labeling and complying with the laws 

 of the various States, should in all cases be conducted by the 

 official methods. Albert has made a resume of methods applica- 

 ble for factory control, and these are given here for convenience, 

 although they are, in many respects, but condensed statements 

 of methods already described. 34 



157. Reagents. Molybdate Solution. One hundred and ten 

 grams of pure molybdic acid are dissolved in ammonia of nine- 

 tenths specific gravity and diluted with water to one liter. The 

 solution is poured into one liter of nitric acid, of one and two- 

 tenths specific gravity, and, after standing a few days, filtered. 



Concentrated Ammonium Nitrate Solution. Seven hundred 

 and fifty grams of pure ammonium nitrate are dissolved in water 

 and made up to one liter. 



Magnesia Mixture. Fifty-five grams of magnesium chlorid, 

 70 grams of ammonium chlorid and 130 cubic centimeters of am- 

 monia of nine-tenths specific gravity are dissolved and diluted with 

 water to one liter. 



Two and One-Half Per Cent. Ammonia. One hundred cubic 

 centimeters of ammonia of nine-tenths specific gravity are diluted 

 with water to one liter. 



Joulie's Citrate Solution. Four hundred grams of citric acid 

 are dissolved in ammonia of nine-tenths specific gravity and di- 

 luted to one liter with ammonia of the same strength. 



Wagner's Citrate Solution. One hundred and fifty grams of 

 citric acid are exactly neutralized with ammonia, then 10 grams 

 of citric acid added and diluted to one liter with water. 



Sodium Acetate Solution. One hundred grams of crystallized 

 sodium acetate' are dissolved in water, treated with 100 cubic 

 centimeters of acetic acid, and diluted to one liter with water. 



Calcium Phosphate Solution. About 10 grams of dry, pure 

 tribasic calcium phosphate are dissolved in nitric acid and dilu- 

 34 Zeitschrift fur angewandte Chemie, 1891, 4 : 278. 



