Mar. 1, 1925 
Calorimetric Investigations with Cattle 
401 
during the drying of the daily samples 
appears, therefore, to be the more ex¬ 
tensive factor of error, but since there 
must have been some error on both 
these accounts the true figure for dry 
matter must have been higher than the 
one and lower than the other estima¬ 
tion, and there being no means of 
determining this intermediate figure 
exactly, the average of the two was 
used. 
Table VI gives the results of the 
determinations of dry matter in the 
composite sample, the average of 
determinations in the daily samples, 
and the average of the two, as well as 
the possible error, in per cent and in 
grams of dry matter per day. 
The differences between the two 
percentages of dry matter are fairly 
uniform. The average of all differ¬ 
ences (omitting that of experiment 
221c, 886 I) is 0.869 per cent. This 
means that, on the average, the dry 
matter as determined on the composite 
is about 0.9 per cent higher than the 
true average of the daily determina¬ 
tions or that the possible error of using 
the average of the two is about ±0.4 
per cent. The magnitude of the error 
in grams per day obviously depends 
on the fresh weight of the material, 
and ranges in these experiments from 
±14.4 gm. to ±113.2. It should be 
understood that the data presented 
apply only to the particular conditions 
and procedures which prevailed in 
this work. 
An error in the determination of dry 
matter involves corresponding errors 
in energy, nitrogen, and carbon as 
determined on the dried material, all 
being in the same direction. These 
possible errors have been computed in 
Table VII, using the data from exper¬ 
iments 22 If and 22lg as examples. 
The possible errors in energy range 
from ±135.4 Calories to ±451.9 cal¬ 
ories; the possible errors in nitrogen 
are small, ranging from ±0.59 gm. to 
±2.46 gm.; the possible errors in 
carbon range from ± 13.49 gm. to 
±44.96 gm. 
Table VI .—Possible error of determinations of dry matter in feces-and-urine 
mixture 
i 
Experiment and period 
Fresh 
weight 
I 
Composite 
sample 
Dry matter 
II 
Triie aver¬ 
age of daily 
samples 
III 
Average of 
I and II 
| Possible error 
Grams 
221 c: 
Grams 
Per cent 
Per cent 
Per cent 
Per cent 
dry matter 
8851..... 
20,038.4 
13.182 
12.312 
12.747 
±0.435 
±87.2 
885 II... 
14,044.4 
13.170 
11.946 
12. 558 
± .612 
±86.0 
885 III.! 
14, 785.4 
15.050 
13.810 
14.430 
± .620 
±91.7 
886 1... 
17,137.8 
12.595 
15.097 
13.846 
=F1.251 
=F214.4 
886 II........ 
12 ,121. 0 
13.044 
12.242 
12.643 
± .401 
±48.6 
886 III... 
17,364.2 
15.973 
14. 669 
15.321 
± .652 
±113.2 
221 d: 
885 1....1 
9,415. 2 
14. 740 
13. 848 
14.294 
± .446 
±42.0 
885 II.....i 
16,614. 8 
12 . 268 
11. 520 
11. 894 
± .374 
±62.1 
885 III____ 
10,410.8 
13. 391 
12. 555 
12.973 
± .418 
±43.5 
886 1...... 
9,258. 9 
15. 511 
14. 523 
15. 017 
db .494 
±45.7 
886 II... 
15,567. 8 
14.429 
13. 715 
14.072 
± .357 
±55.6 
886 III--.... 
! 10,464. 6 
13.178 
12.468 
12. 823 
± .355 
±37.1 
221 e: 
i 
885 I____ 
11,784. 9 
14.098 
885 II..... 
8 ,937.8 
13. 954 
13.094 
13. 524 
=fc .430 
±38.4 
886 I...-.. 
17,992.2 
15.942 
14. 956 
15.449 
± .493 
±88.7 
886 II... 
15,846.1 
15.681 
15.007 
15. 344 
± .337 
±53.4 
874 I.... 
14, 513.1 
17.373 
16.263 
16.818 
± .555 
±80.6 
874 II____ 
11,900.2 
17.099 
16. 857 
16. 978 
± .121 
±14.4 
221 f: 
874 I.... 
13, 370. 7 
17.131 
16.163 
16. 647 
± .484 
±64.7 
874 II___ 
9,018. 0 
17.362 
16. 206 
16. 784 
± .578 
±52.1 
887 I_ 
1 13,424. 0 
14. 514 
13.588 
14.051 
± .463 
±62.2 
887 II__ 
8,909.0 
14. 992 
14.110 
14. 551 
± .441 
±39.3 
886 1____ 
20,344.0 
16.073 
15.099 
15. 586 
± .487 
±99.1 
886 II..... 
; 18,668.0 
14.830 
14. 510 
14. 670 
zb* . 160 
±29.9 
221 g: 
( 
8871... 
16, 924. 0 
16.903 
15. 965 
16. 434 
db .469 
±79.4 
887 II--.-.. 
10 ,220. 0 
14.178 
13.322 
13. 750 
zb .428 
±43.7 
887 III.... 
14,022. 0 
15.126 
14.416 
14. 771 
zb .355 
±49.8 
887 IV„... 
18, 531. 0 
16.102 
15.442 
15. 772 
dz .330 
±61.2 
19974—25f-2 
