10 



As the 1892 samples of bone-meal gave such poor results on soils 

 low in phosphoric acid," new samples for the 1893 experiments were 

 selected. These were numbers 5 and G of page 8. 



In these experiments barley was grown on a sandy soil low in 

 phosphoric acid. From the results, as found in Table II, the fol- 

 lowing conclusions are drawn : 



1. The new samples of bone-meal act no more favorably than those 



used in the former experiments. See column a. in next table. 

 The maximum yield, according to the above figures, was pro- 

 duced by the application of 1.2 grams of phosphoric acid per 

 pot, but the increased yields, produced by the bone-meal 

 phosphoric acid, are here again extra or dinar ily loiv. 



2. The barley plants are not able to take up significant quantities 



of phosi)horic acid from the bone-meal, although considerable 

 quantities were taken up from the superphosphate. See 

 column b. 



3. The same result was yielded by the experiments in which soluble 



])hosphoric acid, reinforced with bone-meal, was used. The 



following are the figures obtained in these cases : — 



a. Experiments with 0.3 gram of soluble phosphoric acid as chief 



fertilizer. This weight of superphosphate acid must have given, 



according to Table II, an increase of yield of 83.65 grams and furnished 



0.100 gram of phosphoric acid to the barley. 



Phos. Acid applied. Increase of yield. Increase of jield due to bone-meal. 

 Grams. Torm. Grams. Grams. 



0.3 Superphos. 1 gave 86.66 3.01 



0.3 Raw bone-meal J ^ 



0.3 Superphos. ) nc .to ii ,-o 



rv u /-., i 1 1 hg^ve 95.28 11.63 



0.3 Glue-free bone-meal j '=' 



Average 90.97 7.32 



The 0.3 gram phosphoric acid should have produced an increase 

 of yield of 83.65 grams, but the 0.3 gram of bone-meal phosphoric 

 acid gave the diminutive increase of 7.32 grams. 



