BARN-YARD MANURE. 231 



direction of seeking out new supplies of plant-food would be 

 practically aimless and absurd. But this is not the case. The 

 exhaustive process is continuous in all civilized communities, 

 and it is impossible, in densely peopled sections, to maintain a 

 satisfactory balance between supply and demand. 



It was very natural, then, that early in the history of chem- 

 istry as an exact science, it should be called to the investigation 

 and determination of the chemical nature of that material, 

 which common observation and experience had taught to possess 

 the natural food of plants. As regards its superlative value, no 

 one has ever entertained a doubt, either before or since the 

 field of chemical investigation was fairly opened. What is 

 its composition ? Allow me to present the results of some 

 determinations of my own on this point. A parcel obtained 

 from the yard of a neighbor, which, under the conditions in 

 which it was produced and preserved, may be regarded as a fair 

 representative of the article as furnished by ordinary farmers, 

 gave the following results : A portion weighing 7,280 grains 

 was carefully dried in a porcelain dish over a water-bath, and it 

 was found to lose of water 5,960 grains, leaving of dry matter 

 1,320 grains. Of the residuum thus freed from moisture, 455 

 grains were placed in a platinum capsule and carefully ignited, 

 thus removing the combustible or carbonaceous matter made 

 up of the elements — oxygen, hydrogen and carbon. The 

 resultant ash weighed 177 grains, showing a loss of volatile or 

 combustible elements amounting to 278 grains. In order that 

 the results of the analysis may be clearly understood, it may be 

 desirable to present them without regard to fractional parts, 

 and to estimate by the whole amount experimented with, viz., 

 7,280 grains. This amount gave of water, 5,960 grains ; com- 

 bustible or carbonaceous matter, 806 ; nitrogen, 29 ; potash and 

 soda, 41 ; lime, 43 ; magnesia, 14 ; phosphoric acid, 15 ; sul- 

 phuric acid, 11 ; chlorine, 14 ; silicon or sand, 335 ; oxide of 

 iron and alumina, 22. The points in this examination which 

 will doubtless appear most striking, are the large amounts of 

 worthless material which constitute the bulk of barn-yard 

 manure, the water and sand greatly predominating over every- 

 thing else. 



A better idea of this may be obtained if the results of the 

 analysis are applied to a larger amount of manure, which will 



