EXPERIMENTAL MILLING AND BAKING. 
37 
been added sodium thiosulphate 10 in the ratio of 1 gram to every 
determination; concentrated sulphuric acid, free from nitrate, 
specific gravity 1.84; mossy zinc, mercuric oxide (yellow), 1 per cent 
alcoholic solution of methyl red indicator, C. P. sodium sulphate. 
Determination. — Place 2 grams of the sample in a Kjeldahl flask 
and determine the nitrogen as follows: Add approximately 0.7 gram 
of mercuric oxide, or its equivalent in metallic mercur}^, 10 grams 
of sodium sulphate, and 25 cubic centimeters of sulphuric acid to 
the flask and place on the digestion frame in an inclined position. 
Adjust the heat so that the contents of the flask will be covered and 
digest for 15 or 20 minutes after the solution becomes colorless or 
straw-colored. Cool and dilute with 200 cubic centimeters of dis- 
(USi 
Fig. 
-Moisture tester for rapidly determining the moisture content of cereal gi 
substances. Gas-pressure regulator on gas supply line in foreground. 
i other 
bumping, 
tilled water. Add a small piece of mossy zinc to prevent 
then sufficient saturated sodium hydroxide solution containing 
1 gram sodium thiosulphate per determination to make the reaction 
strongly alkaline, pouring this solution down the neck of the flask 
without mixing until after connecting with the distilling bulb. 
Distill off the ammonia into a definite amount (20 or 25 cubic centi- 
meters) of standatd N/5 hydrochloric acid which has been placed 
in the receiving bottle and diluted with about 50 cubic centimeters 
of neutral distilled water. Continue the distillation for 30 to 50 
minutes when 100 to 150 cubic centimeters of distillate will have been 
collected. Titrate to the neutral point with standard N/10 sodium 
i° The use of sodium thiosulphate as a mercury precipitant is not as yet used by the Association of Official 
Agricultural Chemists, but has been found to give just as accurate results, and furthermore has the 
threefold advantage of being less expensive than potassium or sodium sulphide, is easier to get into solu- 
tion, and when combined with the caustic soda speeds up the test. 
