40 



BULLETIN 102, TJ. S. DEPARTMENT OF AGRICULTURE. 



PERCENTAGE OF TOTAL SAMPLES 



BELOW 



1- 



10 20 30 40 SO 60 lO 80 90 /0( 





















I 





31 





















1 























f 





30 





















j 























| 





29 





















1 























I 





2b 





















I 























f 





21 





















j 























f 





26 





















/ 

























/ 





25 















































1 



24 

 23 

 22 

 21 























X 



k 



Q 



























































































20 

 19 

































\S 



































18 

 17 

 (6 

 15 

























































































BELOW 























111 

 of 

 to 



Assuming that 30 c. c. correctly discriminates in a general way 

 between good and bad corn, it becomes necessary, in order to make 

 the acid test a test of value, to establish limits below 30 c. c. which 

 will relatively classify the good corn according to its degree of quality 

 and soundness. 



Results of corn-acidity investigations show that theoretically 

 quality and soundness vary directly in proportion to the degree of 

 acidity of the corn. All corn shows acidity of a certain degree. 



The minimum degree of 

 acidity is represented 

 the corn at the time 

 harvest, and is found 

 vary between the limits of 

 9 or 10 and 15 or 16 c. c, 

 having never been found 

 to exceed 20 c. c. 



Covering a period of 

 three years, approximately 

 10,000 samples were tested 

 for degree of acidity. 

 These samples included 

 seed corn as well as corn 

 from the harvest field, corn 

 as stored on the farm and 

 as found through all stages 

 of commercial handling, 

 including transportation 

 and storage, and showed 

 ranges in the degree of 

 acidity from 9 to 10 c. c. 

 to over 100 c. c. Of the 

 corn arriving at terminal 



Fig. 29.— Curve showing the percentage of samples of corn ryioi'lrpf g throughout the 

 tested for degree of acidity which fell below 15, below 16, & 



below 17, and so on up to and including 32 c. c, representing COimtrV, between 75 aild 



approximately 8,000 cars received at four principal termi- cq -p.™, f»gv,f qP flip OMTS as 

 nal markets. * ■ *" 



sampled showed acidity 

 below 22 c. c, about 90 per cent was below 26 c. c, and approxi- 

 mately 4 or 5 per cent was above 30 c. c. (Figs. 29 and 30.) 



From the results of mechanical analyses of samples representing 

 cars arriving at terminal markets (fig. 21) the average degree of 



acidity of the separations shows as follows : 



c. c. 



Sound kernels 19. 5 



Broken kernels 22. 5 



Damaged kernels, exclusive of heat damage 4 L. 2 



Slightly heat-damaged kernels 41. S 



Badly heat-damaged kernels 50. 8 



