6 



The following investigators have published reports on this work : 

 Farriugton* ; Armsby and Caldwell^ ; P. Wagner^ ; Marek^ ; Hol- 

 defleiss'^ ; Ulbrieht^ ; Kellner and Japanese assistants'^ ; Steffek 

 and Maercker^. 



These experimenters obtained somewhat varying results. Armsby 

 and Caldwell have carried on for over four years a valuable 

 series of experiments. 



They apparently show that on lime, peat and sandy soils phos- 

 phoric acid in bone-meal is profitably applied, and that on such soils 

 the effect is inversely as the solubility of the phosphoric acid. This 

 is a conclusion at variance with the opinion held by many, that only 

 quick acting manures are profitable. A large part of the fertilizing 

 effect of bone-meal must be ascribed to its nitrogen. 



WAGNER'S (Darmstadt) RESULTS. 



The publication by P. Wagner, of results obtained in 1889, first 

 raised serious doubt as to the supposed superiority of bone-meal phos- 

 phate. They are summarized as follows : 



1. Bi/e-cnltures soivn with Clover. 1889. 

 With phosphoric acid in superphosphate, 100 lbs. of crop 



With same quantity in ground Thomas Slag, 59 " " 



With same quantity in bone-meal, 8 " " 



2. Experiments on Clay Soil. 

 First year : 



With phosphoric acid in superphosphate. 



With same quantity in bone-meal. 

 Second year : 



With phosphoric acid in superphosphate. 



With same quantity in bone-meal, 

 Third year : 



A¥ith phosphoric acid in superphosphate. 



With same quantity in bone-meal. 

 These figures present a surprising result, 

 first year shows in one case only 8 per cent, and another only 5 per 

 cent of the effect of the superphosphate, but it is also far behind the 

 superphosphate in its after effect. 



STEFFEK & MAERCKER'S (Halle) EXPERIMENTS. 

 These include Series A to F ; pages 6 to 18, and Tables I. to VI. 



