215-217] 



Analysis of Bone Meal 



135 



215. Phosphoric Acid. — This is estimated in the 

 nitrate from the lime and sand, exactly as described in para- 

 graph 199 for mineral phosphates. 



216. Nitrogen. — Two grams are used for this esti- 

 mation, which may be done by either of the two methods 

 described in paragraphs 86-95. 



217. Calculation of Results.— From the Mg 2 P 2 7 

 calculate the percentages of P 2 5 and Ca 3 P 2 8 . From the 

 CaC0 3 calculate the percentage of CaO. Find the excess of 

 CaO as in mineral phosphate analysis. 



The excess of CaO is used as a check on the accuracy of 

 the rest of the analysis, which is put out in this form : 



It is not usual to state the excess of lime, but it is always 

 well to calculate it out. It should amount (in bones) to a little 

 less than half the ' CaC0 3 , &c.,' which is the difference between 

 the sum of the other percentages and 100. 



The percentage of nitrogen, multiplied by 17 and divided 

 by 14, gives the percentage of ammonia. 



The analysis of bone ash is exactly similar to that of bone 

 meal, except that the nitrogen is not estimated. 



