8 
BULLETIN 
839, U. S. 
DEPARTMENT OF AGRICULTURE. 
slides for the same day and averaging the three results to determine 
the analyst's daily variation. This is calculated for each analyst. 
The ultimate daily variation is the average of the daily variation of 
the two analysts computed for each day. The daily variation for 
each analyst is shown in Table 4. 
Table 4. — Daily variation for each analyst. 
Variation. 
Bran particles. 
Hairs. 
Slide. 
Jan. 7, 
1918. 
Jan. 8, 
1918. 
Jan. 9, 
1918. 
Jan. 7, 
1918. 
Jan. 8, 
1918. 
Jan. 9, 
1918. 
A 
Keenan. 
89 
60 
84 
77 
108 
83 
88 
93 
85 
79 
54 
63 
65 
98 
81 
86 
88 
76 
81 
51 
68 
66 
105 
77 
86 
86 
76 
61 
59 
68 
62 
55 
61 
59 
58 
60 
67 
51 
67 
61 
55 
53 
62 
56 
63 
65 
B 
59 
C 
68 
Analyst's daily 
64 
A... 
Lyons. 
54 
B 
55 
c 
63 
57 
60 
The results in Table 4 seem to indicate that on January 7, 1918, 
there was a tendency to count higher on bran particles than on the 
other days. It is believed, however, that this was in whole or in part 
due to the clearing action of the glycerin employed to preserve the 
slides for counting on subsequent days, which tended to make the 
identification of the bran particles more difficult after the first day. 
SLIDE VARIATION DUE TO LIMITS OF ACCURATE WEIGHING OF THE TEST PORTION 
OF FLOUR. 
In order to determine the absolute variation between the slides, 
it is evident that an average must be obtained from which the personal 
variations and the daily variations have been eliminated as far as 
possible. This is accomplished by computing for each slide the aver- 
age of all counts made on bran particles, and also making a similar 
computation for the hair count (Table 5). 
Table 5 — 
-Counts 
of bran particles and hairs 
on slides. 
Bran particles. 
Hairs. 
Slide A. 
Slide B. 
Slide C 
Slide A. 
Slide B. 
Slide C 
89 
79 
81 
108 
98 
105 
60 
54 
51 
83 
81 
77 
84 
63 
68 
88 
86 
86 
61 
67 
65 
55 
55 
54 
59 
51 
59 
61 
53 
55 
68 
67 
68 
59 
62 
63 
193 
167 
179 
159 
156 
164 
Average slide count. 
