COMMERCIAL FERTILIZERS IN HORTICULTURE. 1 63 



gradually, molded by compelitiou, the necessity for pi'ofit, the 

 relative cheapness of materials, conditions of intelligence or 

 ignorance apon the part of consumers, and, to some extent, by 

 prevailing notions in the scientific world. 



Unfortunately, however, (aud I say this out of a dozen or more 

 years of experience as an inspector of fertilizers) it is the minor- 

 ity of fei'tilizer manufacturers who are making a study of the 

 real needs of agriculture so as to meet these needs with the right 

 amount of the best materials. Too many of them are dealing 

 upon the ephemeral basis of selling the least value in plant food, 

 for the biggest price that competition will allow, rather than upon 

 the more enduring foundation of supplying the most useful 

 compounds for plant nutrition in the right proportions. The 

 methods that govern the patent medicine trade have entered too 

 largely into the fertilizer trade. It is too often a matter of skill- 

 ful advertising, or the canvassing of a shrewd, tonguey agent, 

 rather than a consideration of the real needs of the consumer. 

 The horticulturist, at least, should stand outside these unfortunate 

 conditions, for he, as a rule, is a man who is intelligently study- 

 ing his business. 



In order to get at this matter more in detail, let us consider 

 briefly what fertilizers are aud the sources of the materials that 

 enter into them. 



The superphosphates of the trade are, as you well know, mostly 

 mixtures, in varying proportions, of three classes of compounds, 

 — those containing nitrogen, phosphates of various kinds, and 

 potash salts. The leading ingredient in the matter -of quantity is 

 phosphoric acid, potash standing next in order. 



The principal sources of phosphoric acid are bone in its various 

 forms, — raw, steamed, dissolved bone and dissolved bone black, 

 South Carolina and Florida rock phosphates both crude and 

 dissolved, phosphatic guanos, etc. Jn all these substances the 

 phosphoric acid is combined chiefly with calcium oxide or lime, 

 although one material which is made up mostly of phosphates of 

 iron and aluminum has recently come into some prominence. 

 The availability of phosphoric acid in these several sources of 

 supply is the main point for consideration, and I have this to say, 

 that in so far as it is rendered water-soluble its value is uniform 

 whatever its source. The so-called "reverted" or "citrate 

 soluble " phosphoric acid must also have a practically uniform 



