28 

 Sulfate of Potash-Magnesia, Kainit and "Nitrapo." 



* Two analyses made. 



2 Nitrogen found, 14.32 per cent; guaranteed, 14.80 per cent. 



The presence of chlorine in sulfate of potash is of particular interest in that 

 it may, in a measure, account for at least a part of the chlorine often found 

 in brands of fertilizer for tobacco^ and other crops where sulfate of potash 

 is supposed to be the source of the potash guaranteed. The average of nine 

 analyses of high-grade sulfate gave 2.13 per cent chlorine, or expressed in 

 another way, 2.83 per cent of actual potash (KoO) was present as chloride. 

 The chlorine varied considerably in the different samples, ranging from .70 

 to 3.04 per cent. 



The three samples of sulfate of potash-magnesia showed an average chlorine 

 content of 1.71 per cent. The average percentage of magnesium oxide present 

 in this salt was 11.81, equivalent to 35.26 per cent magnesium sulfate. (To 

 change magnesium oxide to magnesium sulfate, multiply by factor 2.9859.) 



At a recent meeting of the Association of Official Agricultural Chemists, 

 the Committee on Definition of Terms and Interpretation of Results on 

 Fertilizers recommended for final adoption the following definitions as applied 

 to potash salts. They are given here as a matter of record and interest: 

 "Manure salts shall be understood to mean potash salts containing 



high percentages of chloride and from 20 to 30 per cent of potash (K2O). 



The term 'double manure salts' should be discontinued. 



"Sulphate of potash-magnesia is a potash salt containing not less than 



25 per cent of potash (K2O), nor less than 25 per cent sulphate of mag- 

 nesia, and not more than 2.5 per cent chlorine." 



' See page 13, "Percentage, Character and Cost of Plant Food." 



Raw Products supplying Nitrogen and Phosphoric Acid. 



Dry Ground Fish. 

 Brands Substantially Meeting Their Guarantees. 



Manufacturer 



The American Agricultural Chemical Co. . 

 Apothecaries Hall Co 



Armour Fertilizer Works . . . . \ 



The Berkshire Fertilizer Co 



The E. D. Chittenden Co 



A. W. Higgins, Inc 



Nitrate Agencies Co 



Olds & Whipple, Inc 



Sanderson Fertilizer & Chemical Co. . 



The Wilcox Fertilizer Co 



Number 



of 

 Samples 



Nitrogen 



Found 



8.37 

 9.15 

 9.51 

 8.59 

 8.14 

 8.61 

 8.92 

 8.69 

 8.45 

 8.43 

 8.84 



Guaran- 

 teed 



8.23 

 8.23 

 9.05 

 8.22 

 8.22 

 8.22 

 9.05 

 8.23 

 8.23 

 8.23 

 9.04 



Phosphoric 

 Acid 



Found 



9.82 

 7.32 

 5.72 

 8.65 

 7.43 

 7.34 

 7.31 

 5.23 

 7.14 

 9.62 

 7.32 



Guaran- 

 teed 



6.00 

 5.50 

 6.86 

 4.00 

 6.00 

 6.00 

 5.00 

 4.58 

 5.00 

 6.00 

 6.00 



1 Three analyses made 



2 Two analyses made. 



3 1923 stock. 



* Four analyses made. 



