ANALYTIC PROCESSES 23 
Standard acid.—‘/, Sulfuric or hydrochloric 
acid, the strength of which has been accurately 
determined. 
Standard alkali.—% /,, Ammonium hydroxid, so- 
dium hydroxid, or barium hydroxid, the strength 
of which in relation to the standard acid must 
be accurately determined. 
Sodium hydroxid solution—soo grams should 
be added to soo c.c. of water, the mixture al- 
lowed to stand until the undissolved matter 
settles, the clear liquor decanted and kept ina 
stoppered bottle. It will be an advantage to 
determine approximately the quantity of this 
solution required to neutralize 20 c.c. of the 
strong sulfuric acid. 
Indicator —Cochineal solution is recommended 
by the A. O. A. C., but methyl-orange and sodium 
alizarin-monosulfonate are satisfactory. Methyl- 
orange solution should be very dilute; 1 part in 
tooo. A drop is sufficient for 100 c.c. of liquid. 
Phenolphthalein is not well adapted to tritation 
of ammonium compounds. 
Digestion and distillation flasks.—Jena-glass 
round-bottomed flasks with a bulb 12.5 cm. 
long and 9 cm. in diameter, the neck cylindrical, 
15 cm. long and 3 cm. in diameter, flared slightly 
at the mouth. 
Process 
5 c.c. of the sample are placed in a digestion 
3 
