388 SELECTIONS FROM ADDRESSES. 



draw largely on the atmosphere and rain water for their organic 

 aliment. Bnt under the most favorable circumstances, there is 

 reason to believe that the earth parts with not over ten or twelve 

 parts in 100 of the matter organized in the tissues of most cul- 

 tivated plants. If we carefully leach five or ten pounds of rich 

 soil in pure rain water, as it falls from the clouds, for several 

 weeks, and evaporate the water, we shall find that it has ex- 

 tracted a considerable amount of both the combustible and in- 

 combustible food of vegetables. In some cases, the combusti- 

 ble part (organic) exceeds in weight the inorganic part ; in 

 others, the latter is larger than the former. After comparing the 

 results of my own researches upon this point, now extended 

 through many years, with those attained by others, I feel war- 

 ranted in saying that no certain rule can be laid down in ad- 

 vance of an analysis that will fairly express the proportion that 

 the soluble organic matter in a soil bears to the soluble inor- 

 ganic matter. 



One kind of mould, irrespective of its insolubility, differs 

 greatly in economical value from another. Its fertilizing power 

 is mainly governed by the nature of the plants or organized 

 substances that decayed to produce it. Thus, 100 pounds of 

 dry pine saw-dust will form mould much poorer than a like 

 weight of dry clover. In the saw-dust there are only three 

 pounds of nitrogen, in the clover there are twenty-four pounds. 

 Nitrogen is an important element in wheat, and in the muscles 

 and other tissues of animals. Hence a horse will be much 

 more able to work if fed on good clover hay than he would be 

 if kept on pine saw-dust. For a similar reason, wheat plants 

 fed on mould derived from clover will fare better than they 

 would if confined to the organic remains of pine wood. 1000 

 pounds of clover will yield seventy-five or eighty pounds of 

 ashes when burnt ; while 1000 pounds of pine wood will not 

 produce over five pounds. In the mineral food of plants, clover 

 is fifteen times richer than saw-dust. 100 pounds of the flesh 

 of a dead horse (dry weight) and 100 pounds of wheat or rye 

 straw will yield mould of very unequal value. The former 

 will furnish forty-five times more ammonia (nitrogen and hy- 

 drogen) than the latter. By investigations of this character, 



