Series A. Table 1. (1892.) 



A sandy soil, loio in phosphoric acid was used. These experiments 

 were carried out with barley. After the barley, a second crop of pease, 

 vetches and oats was raised, to ascertii in the after- effect. For the purpose 

 of control, each experiment was carried out in triplicate, i. e., in 

 three different vegetation pots. Table I. shows the results which 

 may be thus summarized : — 



1. The effects of the phosphoric acid in the various bone-meals were 



not essentially different. 



2. The effect of each of the bone-meals in the sandy soil, low in 



phosphoric acid, was extraordinarily slight. The following 

 table shows this : — 



The yield of the second crop of pease, vetches and oats should show 

 whether, according to general belief, the slowly acting phosphoric acid 

 of bone-meal is taken up in any considerable quantity by the after-crop. 

 If phosphoric acid in bone-meal can claim a high fertilizing value, 

 and yet cannot show a result with the lirst crop equal to that of 

 phosphoric acid in superphosphate, it must then yield superior 

 results with the second and still later crops. The figures of the last 

 column above prove that even this was not the case, for there 

 was no higher yield as an after-effect of the phosphoric acid in bone- 

 meal than of that in superphosphate, and the quantity of phosphoric 

 acid, which the superphosphate could yield the plant, was far greater 

 than that from the bone-meal. But it should be particularly empha- 

 sized that, even in the after effect, the bone-meals cannot make up 

 for what they have failed to accomplish with the first crop. 



Series B. Table II. (1893.) 



In order to ascertain to what extent bone-meals are capable of adding 

 to a store of easily soluble phosphoric acid, which shall be readily avail- 

 able to the plant, the following experiment was conducted in 1893. 

 Vegetation pots were filled with a sand extremely low in phosphoric 

 acid, and to this was given a supply of varying quantities of super- 

 phosphate, with which were mixed different amounts of phosphoric 

 acid, in the form of bone-meal. 



Although the bone-meal phosphoric acid did not become effective, 

 this was not due to unfavorable conditions. 



