New York Agricultural Experiment Station. 133 



(a) Nitrogen.^-The law requires in a guarantee-statement of 

 chemical composition that the per cent of nitrogen as nitrogen 

 shall be stated. The law does not forbid stating the equivalent 

 of nitrogen in the form of ammonia in addition, but the per cent 

 of nitrogen as nitrogen must be given in any and every case. 

 The indiscriminate and exclusive us of the term " ammonia " 

 in guaranteeing nitrogen is misleading and is no longer per- 

 mitted. 



(6) PhospJioric Acid. — The law requires the per cent of available 

 phosphoric acid to be stated, and, in case of undissolved bone, 

 the per cent of total phosphoric acid. There is nothing in the 

 law to prevent the statement of reverted, soluble, insoluble and 

 total phosphoric acid in addition to the available form; but the 

 per cent of available phosphoric acid must always be stated when 

 present, except in case of undissolved bone. 



The present law differs from the former law in that the former 

 required the separate statement of both soluble and available 

 phosphoric acid and made no provision for undissolved bone. 

 The former law, however, did not require manufacturers to main- 

 tain their guarantee in respect to soluble phosphoric acid. It 

 was deemed wise to have the legal requirements consistent and 

 drop the soluble phosphoric acid from the guarantee, since this 

 is so readily liable to change on standing. The farmer is suffi- 

 ciently protected in requiring manufacturers to observe the guar- 

 antee with reference only to the available form of phosphoric 

 acid. 



In respect to bone, it is well known that the usual chemical 

 methods used in determining available phosphoric acid do not 

 give reliable results when applied to undissolved bone. The 

 former law was not enforced in respect to untreated bone be- 

 cause it was not properly applicable, though technicall}' no ex- 

 ception was made. The present law recognizes a condition which 

 actually exists and makes provision to cover a case which the 

 former law did not reach. 



(c) Potash. — In a statement of chemical composition, the per 

 cent of potash (K~0) soluble in distilled ivater must be given. 



