10 



Over 18 per cent of the total number of brands analyzed failed to meet their 

 guarantee of nitrogen and available phosphoric acid, and nearly 30 per cent were 

 low in potash. In 1925, only 14 per cent failed to pass in nitrogen, 5 per cent in 

 available phosphoric acid, and 17 per cent in potash. This comparison shows 

 an urgent need on the part of the manufacturer for a closer supervision over the 

 chemical control of the fertilizer simples and by-products used in the formulas, 

 as well as in some instances a more liberal margin of overruns in the guarantees. 



Four more brands showed serious commercial shortages than for the previous 

 season. In some instances where several samples of a given brand have been 

 analyzed, individual analyses may show a commercial shortage of over $1 per 

 ton, but the average of all of the analyses may show no commercial shortage. Such 

 brands are not recorded in this group as commercially deficient, although the 

 sample found deficient is published with appropriate footnote in table listing the 

 commercially deficient brands. 



Mixing EflSciency. 



The following table gives the average margin of overruns over the minimum 

 guarantee as provided by each manufacturer having four or more brands registered 

 and sampled, on the assumption that the tonnage sold, guarantees made, and 

 results of sampling and chemical analyses give a fair representation of the com- 

 position of the tonnage of each grade counted. 



The above table shows that 18 of the 26 manufacturers listed had an overrun 

 in all three elements; 23 showed an overrun and 3 a shortage in nitrogen; 21 

 showed an overrun and 5 a shortage in potash; and all but one showed an overrun 

 in available phosphoric acid. The average marginal overrun of the 26 manu- 

 facturers was .07 per cent less for nitrogen, .17 per cent less for available phosphoric 

 acid, and .08 per cent less for potash, than during 1925. It is likely that this fact 

 may in a measure explain the increased number of deficiencies noted during the 

 year's inspection. 



