CHAPTER CXXXV. 



ANALYSIS OF BONE-MEAL. 



/ T*O analyse a sample of Bone-meal, the following method 

 is to be adopted for determining severally the following 

 constituents viz., Moisture, Organic matter, Sand, Phosphates, 

 Calcium Carbonate, and Ammonia or Nitrogen. 



(1) Moisture. 3 grams of the powdered bone-meal should 

 be weighed out in a watch-glass. This should be left in a 

 water-oven. The loss of weight (when the weighing is 

 found to remain constant next day), is due to moisture. 



(2) Organic matter. One gram of the bone-meal 

 should be weighed out in a platinum crucible. This is ignited 

 in low heat. When all the black particles disappear, and 

 the residue in the crucible appears white, it is put aside in 

 the desiccator, and when cool, weighed. The loss of weight 

 is due to the joint loss of moisture and organic matter in 

 one gramme of the meal, but the amount of moisture has 

 been already determined. The remainder should be calculated 

 as due to organic matter. 



(3) Sand. The residue in the crucible should then 

 be emptied into a beaker, the crucible being also washed out 

 into the beaker with HC1. A little more HC1 is then added 

 to the substance in the beaker ; and the beaker left in the 

 sand bath for that day. Next day, the contents of the 

 beaker are filtered through ordinary filter-paper ; the sand on 

 the filter-paper is washed a few times, dried in water-oven, 

 ignited in the crucible, and weighed, when cool. The 

 increase of weight of the crucible gives the weight of sand 

 in a gram of bone-meal. 



