COMMERCIAL FERTILIZERS. 201 



lieved to represent the average cost of fertilizers like the samples analyzed, when 

 supplied at retail in commercial centers ; but a sensible man will neither live en- 

 tirely on corn-bread because it is cheap, nor on venison because it commands a 

 high market value. So, in selecting a fertilizer, the farmer should observe what 

 brands supply the soluble (quick-acting) or insoluble (slow-acting) phosphoric 

 acid in requisite amounts, with any desired proportions of potash and ammonia. 

 ^' Ee verted " phosphoric acid is intermediate in properties between the ''soluble " 

 and " insoluble." The "potash" reported is soluble in water, and therefore avail- 

 able as plant food. "Ammonia " includes the total nitrogen from whatever source. 

 Fragments of hoof, hair and even leather scraps yield ammonia when ignited with 

 soda-lime in the process of analysis, but these resist decomposition in the soil a 

 long time, and therefore are of less actual value to the farmer than ammonium 

 salts, nitrate of soda, dried blood, fish scrap and similar materials. The ammonia 

 (or nitrogen) of a commercial fertilizer, if drawn from the standard sources, is the 

 most expensive ingredient, and purchasers should not waste this by applying it in 

 large quantities to fields that still have a fair amount of organic matter. 



A careful study of the analytical table ivill show the character of the samples sent to this 

 office. Numbers 103-105 were inadvertantly published last year, with the percent- 

 age of fertilizing constituents calculated to the dried substance. The figures given 

 below represent the actual percentages in the samples, as received at this office. 

 Of course these will vary with any changes in the amount of hygroscopic moisture. 



