6 BULLETIN 102, U. S. DEPARTMENT OP AGRICULTURE. 



(2) Standard alkali solution: Hundredth normal potassium hy- 

 droxid (KOH) solution has been found to be the solution best adapted 

 for making this determination, but hundredth normal sodium 

 hydroxid (NaOH) solution will be found satisfactory if potassium 

 hydroxid is not obtainable. The standard alkali solution should be 

 prepared from the fused KOH or NaOH sticks, purified by alcohol, 

 or bought ready for use from a dealer in fine chemicals, as the one 

 making the test desires. The solution is apt to deteriorate on standing 

 for any considerable length of time, and for that reason it is best to 

 buy or make up in small quantities. 



(3) Phenolphthalein: A solution of phenolphthalein containing 

 one gram of phenolphthalein in 300 c. c. of alcohol has been found to 



Fig. 6.— Filter stand, showing arrangement of funnels, graduates, flasks, and beakers. 



be the most satisfactory indicator. Be careful to mix the solution 

 thoroughly. 



(4) Distilled water. 



DEGREE OF ACIDITY OF CORN. 



CORN SELECTED FOR SEED. 



Table I shows the degree of acidity and the percentage of germina- 

 tion of corn selected for seed. The samples from the crop of 1912 

 represent Illinois corn selected by individual farmers. The samples 

 from the crops preceding 1912 represent corn selected for seed by 

 various State experiment stations, except that the samples from 



