18 



phosphoric acid, 49 parts in the dissolved raw bone-meal, and 32.6 

 parts in the dissolved glue-free bone-meal. 



The experiments show, therefore, that by a small addition of 

 sulfuric acid to bone-meal, fertilizers are produced which in their 

 first effect stand very near the superphosphates, and under some 

 circumstances equal them. In their after-effects they are verj' good, 

 and, in the long run, better than the superphosphates. Such prepa- 

 rations are therefore better suited for stocking lands with phos- 

 phoric acid than are the superphosphates (i. e. soluble phosphoric 

 acid preparations) . Whether or not similar preparations may advan- 

 tageously be made from raw mineral phosphates must be determined by 

 experiments. Sulfuric acid acts upon them more slowly and, accord- 

 ing to experience, an insufficient addition of sulphuric acid proihices 

 more one-lime phosphate and free phosphoric acid than with the 

 bone-meals, while a large portion of the three-lime phosphate remains 

 undecomposed. 



This danger does not appear to be present in so greata degree with 

 the bone meal, and very likely the future bone-meal industry may 

 include the preparation of these varieties of half-products (dissolved 

 bone-meals) with a high fertilizing value. 



Vegetation experiments not j^et complete, apparently show that 

 these half-products act almost as well as superphosphate, the same 

 amount of phosphoric acid being applied. 



REFERENCES. 



1. Die rationelle Diingung etc., etc.. Press of Winter, Darm- 

 stadt, 1891. 



2. tjber die Phosphorsiiure Wirkung der Knochenmehle, Press of 

 Paul Parey, Berlin, 1895. 



3. Phosi)horic anhydride (P.,Og) is here called phosphoric acid. 

 This is in accord with most agricultural writers. For the same 

 reason sul|)huric anhydride, (SOg) is called sulfuric acid. 



4. New Hampshire Agricultural Report 1888. 



5. Pennsylvania " " 1888 pp. 5-19, also 



" " " 1889. 



6. Liebig's Preisschnft, Press of G. Schonfelds, Dresden, 1889. 



7. Das Knochenmehl etc., etc , Press of Paul Parey, Berlin, 1890. 



8. Jahresbericht d. a. c. Versuchsstation zu Dahme, Press of A. 

 Mieck,Prenzlau, 1893. 



9. Landwirthschaftliche Versuchsstationen, 1892 and 1894. 



10. J. B. Lindsey in Experiment Station Record, Washington, 

 D. C, Vol. VII, p. 80 and following. 



11. One millimeter is very nearly four hundredths of one inch. 



