32 



BULLETIN 102, U. S. DEPARTMENT OF AGRICULTURE. 



of acidity found in samples of the high grades compared with the 

 greater range in degree of acidity of samples in the lower grades, 

 and also to the uniform low degree of acidity of the corn marketed 

 in 1913 as compared to the acidity of the 1912 receipts (crop of 1911). 

 Table XVI represents a summary of figures 24a- and 24(3. 



Table XVI. — Sam-pies of corn analyzed for acidity at a principal terminal market from. 

 December, 1911, to May, 1913, inclusive, showing the average percentage of sound corn 

 and the percentage of the total number of samples falling within stated acidity ranges. 



Samples. 



Range of acidity (c. c). 



Below 22. 



22.1 to 26. 



20.1 to 30. 



Above 30. 





1,909 

 77.9 

 92.9 



314 



142 



87 



Percentage of total number of samples 



Average percentage of sound corn found in samples 



12.8 



8S.0 



5.8 

 84.4 



3.5 

 57.9 



RELATION OF COMMERCIAL GRADES TO DAMAGED KERNELS. 



By comparing the degree of acidity found in samples with the per- 

 centage of damaged kernels found in the same samples by critical 

 mechanical analysis it will be seen that the acid test is a factor in the 

 commercial grading of corn. This fact is clearly brought out in 

 Tables XVII, XVIII, and XIX, and in figures 25 to 33, covering 

 samples representing approximately 2,500 cars received at a principal 

 terminal market. 



Table XVII shows the results of acid tests and mechanical analyses 

 for damaged kernels made with samples representing grades No. 2, 

 No. 3, No. 4, and sample, respectively. Attention is called to the in- 

 crease in the percentage of damaged kernels with the increase in the 

 range of degree of acidity in each grade, and to the uniformly low 

 percentage of damaged kernels found in samples which showed a de- 

 gree of acidity below 22 c. c, irrespective of the grade. 



Table XVII. — Samples of corn analyzed for acidity, showing the percentage which fell 

 within stated ranges, the average heat damage, and the average damage other than from 

 heat of samples in each range. 





Total samples. 



Average 



damage 



other 



than from 



heat (per 



cent). 



Heat-damaged samples. 



Samples and acidity range. 



Number. 



Per cent. 



Number. 



Per cent. 



Average 

 (per 

 cent). 



No. 2 corn: 



209 

 56 

 5 

 



704 



131 



44 



6 



853 

 95 

 65 

 40 



141 

 . 37 



23 

 41 



77.1 

 20.6 



1.9 







79.6 

 14.8 

 4.9 

 .67 



81.0 

 9.05 

 6.1 

 3.81 



58.3 

 15.4 



9.6 

 16.7 



4.82 

 4.90 

 6.13 











0. 95 



2.0 



















No. 3 corn: 



Below 22 c. c 



5.9 

 7.37 

 8.72 

 13.47 



5.31 

 12.04 

 17.57 

 18.52 



5.21 

 10.66 

 10.91 

 14.94 



1 

 

 

 



1 



3 

 



6 

 11 

 12 

 28 



.14 



10.2 



















No. 4 corn: 



Below 22 c. c 



.35 

 1.05 

 4.61 



21.3 





6.45 





19.0 







Sample grade: 



Below 22 c. c 



4.25 

 29.72 

 52.17 

 68.29 



17.9 





26.9 



Between 26.1 and 30 c. c 



36.9 





72.4 







