The Wagner experiments awakened solicitude among the bone- 

 meal manufacturers and this, doubtless, was the reason why the 

 " Bone-meal Manufacturers Association " of Saxony appealed to the 

 Halle Experiment Station to test the question, and appropriated for 

 this purpose a considerable sum. 



Steffek & JMaercker^, for the Station, complied with the request 

 and obtained, after four yeai-s, the results presented in the following 

 pages. These proved a severe disappointment to the bone-meal 

 manufacturers and also a surprise to the experimenters. They are, 

 however, in accord with the statements of Wagner^, and the experi- 

 ments were executed wnth great care and deliberation. 



All of these experiments were conducted in the Wagner "Vegeta- 

 tion pots." These are water-tight, upright cylinders, open at the 

 top, made of sheet zinc, 7.9 inches in diameter and 7.9 inches l)igh, 

 standing on three legs 2.5 inches high (or of still other dimensions) i*^. 



Professor Wagner^ " has developed this method into a sharp analytic 

 system, for determining accurately' the relative field value of all 

 manurial substances. It is simple enough for any one to carry out, 

 and by no other method can equally good results be obtained. 



The claim has been made that this mode of testing is not a fair 

 one for the bone-meal, because the latter cannot act so effectively as 

 in the open field. It has been repeatedly shown, however, that with 

 every other kind of fertilizing material, results are obtained in the 

 pots fully as favorable to the fertilizer, as those obtained in the field. 

 Generally they are more favorable. There is no good reason for 

 supposing the method to be prejudicial to the interests of bone-meal 

 alone. No pains were spared to so arrange the tests as to get, if 

 possible, favorable results from the bone-meals. Not in a single 

 instance has such an end been reached. 



Investigations with bone-meal, previous to the work at Halle, had 

 been subject to criticism, because the materials employed did not 

 represent the average bone-meals of the market. This objection 

 cannot be raised in the present case, because these fertilizing mate- 

 rials were furnished by the Saxon Bone-meal Manufacturers Asso- 

 ciation, with the distinct statement that they were good average 

 commercial articles. They are here described : — 



