26 



per cent., guaranteed, 4.12 per cent.; available phosphoric acid found, 6.45 

 per cent., guaranteed, 6 per cent. 



New England Potato Fertilizer (3-10), No. 506: nitrogen found, 2.40 per 

 cent., guaranteed, 2.46 per cent.; available phosphoric acid found, 10.06 per 

 cent., guaranteed, 10 per cent. 



Parmenler & Pokey Fertilizer Co. — P. & P. Potato Phosphate (4-10), 

 No. 901: nitrogen found, 2.96 per cent., guaranteed, 3.29 per cent.; available 

 phosphoric acid found, 11.23 per cent., guaranteed, 10 per cent. 



Rogers & Hubbard Co. — Rogers & Hubbard's " Bone Base " Soluble 

 Tobacco Manure, 1917, No. 618: nitrogen found, 4.69 per cent., guaranteed, 

 5 per cent.; available phosphoric acid found, 8.62 per cent., guaranteed, 10 

 per cent. This sample was no doubt taken from goods carried over from 1917. 



Two other samples of this brand, made for the 1918 trade, did noi: show a 

 commercial shortage. 



F. S. Royster Guano Co. — Royster's Perfecto Tobacco Formula, Nos. 163, 

 817, 857: nitrogen found, 3.90 per cent., guaranteed, 4.11 per cent.; available 

 phosphoric acid found, 4.33 per cent., guaranteed, 4 per cent. 



Sanderson Fertilizer & Chemical Co. — Double Strength Ammonia Mix- 

 ture, No. 483: nitrogen found, 6.19 per cent., guaranteed, 6.58 per cent.; 

 available phosphoric acid found, 8.14 per cent., guaranteed, 8 per cent. 



QUALITY OF PLANT FOOD IN MIXED FERTILIZERS. 



Nitrogen in Complete Fertilizers. — A study of the nitrogen used in 

 the mixed complete fertilizers for 1918 shows that the average total nitrogen 

 found was 2.85 per cent., nitrates and ammoniates, 1.87 per cent., and organic 

 nitrogen, .98 per cent. According to these figures, 65.5 per cent, of the total 

 nitrogen was found present in the form of nitrates and ammoniates, and 34.5 

 per cent, in organic form. The quality of the organic nitrogen used in these 

 mixtures is indicated by the following averages: water soluble organic, .14 

 per cent.; water insoluble organic, .84 per cent., of which .46 per cent, was 

 found active and .38 per cent, inactive by the laboratory methods. The aver- 

 age total nitrogen in the complete fertilizers had a percentage activity of 86.7 

 per cent., the total organic nitrogen of 61.2 per cent., and the water insoluble 

 organic nitrogen of 54.8 per cent. 



Nitrogen in Ammoniated Superphosphates. — The following data 

 show the quality of nitrogen used in these mixtures: average total nitrogen 

 found, 3.18 per cent.; nitrogen in form of nitrates and ammoniates, 1.73 per 

 cent.; organic nitrogen, 1.45 per cent. From these figures it will be seen that 



