50 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE 
average values for these determinations in samples of flowers and 
stems. ° 
The formula for making the calculations is as follows: 
__ 100 (a-c) 
90: a= 
in which X = percentage of stems in sample. 
a=average percentage of nitrogen or P,O, in flowers. 
b= average percentage of nitrogen or P,O, in stems. 
c=nitrogen or P,O; in sample. 
The value of a differs as to whether the mixture is made with 
open flowers and stems or with closed flowers and stems. 
In the case of open flowers and stems: 
(1) Based on nitrogen values— 
xX 
C—lel6n 
b=0.765 
~~ 100 (1.2672) 
(2) Based on P,O,— 
i—OUD352 
b=0.234 
100 (0.532-c) _ _ 100 (0.532-c) 
ACT 0:632-0.098 Foe eee aa es 
In mixtures of closed flowers and stems: 
(1) Based on nitrogen values— 
G—AL foe 
6=0.765 
100 (1.784—c) _ 
A= 734-0.765 98 (1.784) 
(2) Based on P,O,— 
a=0.691 
6=0.234 
100 (0.691-c) _ 
X ="9 91-0.934 =220 (0.691-c) 
In connection with other observations, the crude fiber determina- 
tion is of value in indicating whether open or closed flowers have been 
used in the mixture. In most cases these mixtures are made from 
open flowers, which are cheaper than closed, and stems, though 
sometimes closed flowers are employed. The question then arises, 
how can the analyst tell whether open or closed flowers have been 
used and which values to apply in the formula. 
This may be determined in the following ways: 
1. Examination by a microscopist will show whether open or 
closed flowers have been used. ‘The presence of a large quantity 
6 In obtaining these averages the results of analyses of all cleaned and uncleaned flowers and stems, and 
also of commercial samples of flowers (with a small part of the stem left attached when harvested), were 
included. Theoretically the averages should have been based either on cleaned flowers, without attached 
stems, and on cleaned stems, or on commercial flowers as marketed (with the dirt and short stems still pres- 
ent), and on commercial stems containing the normal percentage of foreign matter. However, the quantity 
of stems and foreign matter in commercial flowers and the quantity of foreign matter in stems are so small 
that the error introduced in this way is negligible, 
