58 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: 



lOOJa-c) 

 a-b 



in which X = percentage of stems in sample. 



a = average percentage of nitrogen or PjOg in flowers. 

 h = average percentage of nitrogen or P2O5 content of stems. 

 c = nitrogen or P2O5 content of sample. 

 The value of a differs as to whether the mixture is made up with 

 "open" flowers and stems or with ''closed" flowers and stems. 

 In the case of "open" flowers and stems: 



(1) Based on nitrogen values — 



a= 1.267 



5 = 0.765 



100(1.267- c)^ 

 ^ 1.267-0.765 ^^^ ^^-'^^' ^' 



(2) Based on P2O5— 



a = 0.532 



6 = 0:234 



In mixtures of closed flowers and stems: 



(1) Based on nitrogen values — 



■ a= 1.784 

 & = 0.765 



^100 (1.784-c) ^„ ,, ^^, , 

 ^= 1.784-0.765 ^'^ ^^-^^^-'^ 



(2) Based on P2O5— 



a = 0.691 

 6 = 0.234 



100 (0.691 -c)_ 

 ^- "0:691^:07234 -22^ (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 up from 

 "open" flowers, which are cheaper than "closed," and stems, though 

 sometimes "closed" flov/ers are employed. The question then arises, 

 how can the a.nalyst tell whether "open" or "closed" flowers have 

 been used and which values to apply in the formula. 



1 In obtaining these averages the results of analyses of all cleaned and uneleaned 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 marlceted (with the dirt and short stems still pres- 

 ent), and on commercial stems containing the normal percentage of foreign matter. Howevei', the amount 

 of stems and foreign matter in commercial flowers and the amount of foreign matter in stems are so small 

 that the error introduced in this way is negligible. 



