25 



grade represents an arnmoniated superphosphate having a minimum guarantee of 

 5 per cent ammonia, 4 per cent available phosphoric acid and no potash. This empha- 

 sizes the great educational value of considering any brand of fertilizer in terms of the 

 amount of plant food which it carries. The use of the expression "ammonia" in this 

 connection instead of "nitrogen" is to conform to the long-established custom of the 

 trade of quoting and referring to the element nitrogen in terms of ammonia. To con- 

 vert ammonia to nitrogen, multiply by the factor .82. 



The column headed "Approximate Commercial Shortage per Ton" gives the 

 approximate valuation per ton of mixture of the deficiencies or shortages which were 

 discovered by chemical analysis. In arriving at these figures the value of overruns 

 has been used in all cases to offset shortages. The presence of some samples in this 

 table which do not show a commercial shortage is explained as follows: when the 

 original analysis of a composite sample showed serious deficiencies, each sample making 

 up the composite was later analyzed by itself; in some cases it was discovered that 

 the shortage was not common to all, but may have been confined to only one sample; 

 the analysis of each sample is therefore given in order to tell the whole story. 



Under "Nitrogen" the column headed "Proportion in Water Soluble Form" 

 gives that portion of the total nitrogen soluble in water, and includes nitrogen as 

 nitrates and ammoniates and water soluble organic nitrogen, all of which are readily 

 available. The column headed "Quality of Organic" tells whether the water in- 

 soluble organic nitrogen in any given brand tested, according to laboratory methods, 

 high, medium or low in activity. "Good" indicates a water insoluble organic nitrogen 

 activity of 55 per cent or over, "Passed" indicates an activity between 50 and 55 

 per cent. "Inferior" indicates an activity under 50 per cent — all being measured 

 by the alkaline permanganate method. In all cases where a test has run under 50 

 per cent by this method, the fertilizer has been tested by the neutral permanganate 

 method, which gives somewhat more favorable results on organic vegetable am- 

 moniates. All samples which showed a test of 85 per cent or better by this method 

 were passed without question, even though the other method may have shown an 

 activity which placed the sample in the suspicious class. 



Footnotes indicate those brands in which any considerable proportion of the 

 potash is in forms other than muriate. 



The remainder of the table wiU be found self-explanatory. 



In the tables headed "Fertihzer Mixtures Substantially Complying with the 

 Guarantee," the presentation of results has been simplified. The headings will be 

 understood without further explanation. It should be borne in mind that every brand 

 represented in these tables has been just as carefully analyzed in complete detail as 

 have those which appear in the previous pages where detailed results are printed. 

 Moreover, the detailed results will be furnished to any one sufficiently interested to make 

 applicatioji for the same. 



