Farmyard Manure 13 



^. Repeated experiments, however, executed with all care 

 to avoid any possible source of error, have shown me that water 

 dissolves phosphate of lime or bone-earth much more rapidly 

 and to a much greater extent than it has hitherto been supposed. 

 This observation gains much in interest, if it be remembered 

 that the late Mr. Pusey suggested many years ago a method of 

 rendering bone-dust more efficacious as a manure for root- 

 crops. His plan was to place bone-dust moistened with water 

 and mixed with ashes, sand, or other porous matters in a heap, 

 and to keep this heap moist by pouring occasionally water upon 

 it, or, better still, stale urine or liquid manure. The suggestion 

 has been followed by many with much success. But few may 

 have known that by adopting Mr. Pusey's plan of reducing bone- 

 dust still further they have been instrumental in generating that 

 combination which gives peculiar value to superphosphate of 

 lime, namely, soluble phosphate of lime. 



In one of the latest numbers of the ' Annalen der Chemie 

 und Pharmacie,' edited by Liebig, Wohler, and Kopp, Pro- 

 fessor Wohler, of the University of Gottingen, makes the im- 

 portant observation that bone-dust moistened with a little water, 

 in the course of a few days yields a considerable quantity of phos- 

 phate of lime to water, and that this solubility rapidly increases 

 with the putrefaction of the gelatine of bones. My analysis of 

 farmyard manure, made a year before the recent notice, which 

 Professor Wohler gave in the ' Annalen der Chemie,' respecting 

 the solubility of phosphate of lime in water, may be regarded as 

 a confirmation of Wohler 's direct experiments upon bone-dust, 

 as well as an interesting scientific commentary on Mr. Pusey's 

 practical suggestion of rendering bone-dust more efficacious as a 

 manure for root-crops. 



13. The insoluble part of the ash of fresh farmyard-manure 

 includes the sand, earth, and other mineral impurities, which 

 mechanically get mixed with the dung. Most of these impuri- 

 ties are mentioned in the ash-analyses as insoluble silicious matter ; 

 another portion is comprehended under oxides of iron and 

 alumina with phosphates ; and a third part, probably a consider- 

 able portion of the mechanical impurities, is included under 

 lime, for the gravel and soil at Cirencester abounds in carbonate 

 of lime. 



Due allowance must be made for these mechanical impurities 

 in all considerations respecting farmyard manure, otherwise 

 conclusions will be drawn which the facts of the case do not 

 warrant. 



14. Chemically considered Farmyard Manure must be regarded 

 as a perfect and universal Manure. It is a universal manure, 

 because it contains all the constituents which our cultivated crops 



