Shoddy Wheat-Manure Superphosphates. f 15 



Water .(*t #ttV< 9 ' 65 



Chloride of sodium (common salt) 68*63 



Nitrate of soda '47 



Sulphate of soda 3*85 



Chloride of magnesium .. ;. .. *67 



Sulphate of ammonia 9*74 



Organic matter 5*72 



Sand . .. i&i. 1-27 



100-00 



It will be observed that this manure principally consists of 

 common salt, with which is mixed some sulphate of ammonia 

 and soda, and a small proportion of nitrate of soda. A calcula- 

 tion of its money- value shows that 8/. is too high a price for a 

 manure of that description. 



A much better wheat-manure is supplied by a well-known 

 Bristol firm. The composition of this manure was found to be 

 as follows : 



Composition of Wheat-Manure manufactured at Bristol. 



Water 32*80 



Soluble organic matter, or ammonia 12*44 



Soluble or bi-phosphate of lime 6*47 



Soluble fixed alkaline salts 3*70 



Insoluble phosphate of lime (bone-earth) 12-60 



Sulphate of lime (gypsum) 11*43 



Magnesia .. .. .. .. .. .. .. '02 



Insoluble organic matter . '. '. .. .. 15*34 



Sand.. 5*20 



100-00 



Percentage of nitrogen in manure 4-24 



equal to ammonia .. . .. .. .. .. .. 5*15 



The proportion of nitrogenized organic matters and of am- 

 monia in this manure is considerable. It is rich also in soluble 

 and insoluble phosphate of lime, but contains rather too much 

 water. 



Superphosphate oj Lime. The composition of superphosphate 

 of lime varies very much, and with it its commercial value. Some 

 samples are prepared from fresh, others from boiled bones, and 

 still others from bone-ash. Hence the differences in the amount 

 of organic matter which are found in commercial superphosphate. 

 But still greater are the differences in the proportions of soluble 

 and insoluble phosphate of lime, two constituents which princi- 

 pally determine the commercial value of superphosphate. 



A good sample should contain from 6 to 8 per cent, of 

 soluble or bi-phosphate of lime, and double that amount of in- 

 soluble or bone phosphate. 



