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 
hi 1913 as compared to the acidity of the 1912 receipts (crop of 1911). 
Table XVI represents a summary of figures 24a and 245. 
Table XVI. — Samples of corn analyzed for acidity at a principal terminal market from 
December, 1911, to May, 1913, inclusive, shoicing 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 
12.8 
88.0 
142 
5.8 
84.4 
87 
3.5 
Average percentage of sound corn found in samples 
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 X VII 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. 
Tota 1 samples. 
Average 
damage 
other 
than from 
heat (per 
cent). 
Heat-d 
amaged samples. 
Samples and acidity range. 
Number. 
Per cent. 
Number. 
Per cent. 
Average 
(per 
cent). 
No. 2 corn: 
Below 22 c. c 
209 
56 
5 

704 
131 
44 
6 
853 
95 
65 
40 
111 
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 
2 


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 
Between 22.1 and 26 c. c 
.35 
1.05 
4.61 
21.3 
6.45 
Between 26.1 and 30 c. c 
19.0 
Sample grade: 
Below 22 c. c 
4.25 
29.72 
52.17 
68.29 
17.9 
Between 22.1 and 26 c. c 
26.9 
Between 26.1 and 30 c. c. 
36.9 
72.4 
