TESTING WHEAT FOB PROTEIN 
15 
Table 9. — Protein content of 19 samples of wheat run by three methods at two 
different intervals of heat and time 
Series 1 
Series 2 
Sample No. 
High heat, 45 minutes 
Two 
hours 
Kjeldahl 
method 
Medium heat, 60 minutes 
Two 
hours 
Kjeldahl 
method 
Kjeldahl 
method 
K. C. P. 
R. B. 
method 
Gunning 
method 
Kjeldahl 
method 
K. C. P. 
R. B. 
method 
Gunning 
method 
1 
Per cent 
11.86 
12.88 
10.20 
11.00 
13.11 
12.31 
13.22 
13.22 
7.92 
12.82 
10.54 
8.26 
9.92 
12.82 
15.30 
11.41 
10.77 
12.88 
15.36 
Per cent 
11.91 
12.94 
10.26 
11.06 
13.17 
12.37 
13.17 
13.24 
7.86 
12.82 
10.54 
8.26 
9.92 
12.82 
15.30 
11.43 
10.72 
12.88 
15.40 
Per cent 
11.91 
12.88 
10.26 
11.06 
13.17 
12.37 
13.11 
13.22 
7.92 
12.82 
10.54 
8.21 
9.92 
12.82 
15.36 
11.40 
10.66 
12.88 
15.40 
Per cent 
11.86 
12.88 
10.20 
11.06 
13.11 
12.37 
13.08 
13.24 
7.87 
12.82 
10.54 
8.25 
9.97 
12.82 
15.38 
11.40 
10.66 
12.82 
15.43 
Per cent 
11.91 
12.88 
10.20 
11.11 
13.18 
12.37 
13.11 
13.24 
7.87 
12.88 
10.60 
8.26 
9.97 
12.81 
15.33 
11.41 
10.66 
12.88 
15.40 
Per cent 
11.91 
12.88 
10.20 
11.06 
13.11 
12.25 
13.11 
13.22 
7.98 
12.77 
10.54 
8.21 
9.97 
12.82 
15.39 
11.41 
10.66 
12.88 
15.45 
Per cent 
11.91 
12.88 
10.26 
11.06 
13.11 
12.31 
13.11 
13.21 
7.87 
12.82 
10.60 
8.21 
9.92 
12.83 
15.33 
11.41 
10.72 
12.88 
15.40 
Per cent 
11.86 
2 . 
12.88 
3... 
10.20 
4... 
11.06 
5. 
13.11 
6... 
12.37 
7 
13.08 
8. 
13.24 
9 ... . 
7.87 
10 
12.82 
11 
10.54 
12 . 
8.25 
13 
9.97 
14 
12.82 
15 
15.38 
16— 
11.40 
17 
18 
19 
10.66 
12.82 
15.43 
These figures are given for very carefully controlled heat condi- 
tions. It was pointed out earlier that the heat during the day and 
on different days was regulated by means of a gas-pressure reg- 
ulator. This is not the case with most laboratories. It is a com- 
mon observation to note changes in flow of gas as more or fewer 
burners are used. This, of course, will change the flow of heat to 
each individual flask, depending on the number in operation and the 
pressure in the gas mains during the day. It is felt, therefore, that 
in recommending 45 minutes at high heat, the variables mentioned 
will be eliminated, as in niany cases almost complete oxidation was 
obtained at 30 minutes. The same is true for the data at medium 
heat, using 60 minutes. 
Using 2 grams of sample, it will take 60 minutes to complete 
digestion at high heat and 75 minutes at medium heat. This is 
approximately 30 per cent longer time than was necessary with a 
1-gram sample. 
SAMPLING STUDIES 
EFFECT OF DUPLICATE CAR SAMPLING ON PROTEIN-TEST RESULTS 
It is absolutely essential that a car or lot of wheat be correctly 
sampled before proceeding with any test. Questions as to how close 
duplicate samplings of bulk loadings will agree in protein content 
have been frequently raised. For the purpose of obtaining some 
data on this point, duplicate samplings were made of 241 cars of 
wheat as they arrived at the Minneapolis market. Some of these 
cars contained as high as 15 per cent of dockage and represented 
receipts loaded both evenly and unevenly. Each car was sampled 
twice in five different areas by means of the usual grain probe in 
