100 



THE SOUTHERN PLANTER. 



big ftt Geissen, will be considered good authori- 

 ty in regard to the views of Liebig on this point. 

 In a letter to Prof. W ebster, dated Geissen, 

 May !, 1846, he says: 



"You are aware that Boussingault has express- 

 ed the opinion, after a variety of experiments, that 

 the value of manure is in near relation to its per- 

 centage of ammonia. Mulder has, you know, 

 written much in support of the view that ulraie 

 and bumic acids, ulmates, humates, etc., in one 

 form and another, minister largely to vegetation. 



* * Liebig differs from them all. * * He 

 takes the position that the sources of carbon and 

 nitrogen are carbonic acid and ammonia in the 

 air. * * * 



"It is obvious (from analysis Of soils and rain- 

 water) that the ammonia spread on fields in the 

 ordinary distribution of barn-yard products is of 

 no moment. The quantity with usual falls of rain 

 greatly exceeds, in Ike course of a season, any conceiva- 

 ble supply by human instrumentality. * * * 



Careful and numerous analyses of rain water and 

 Snow by Boussingault, Lawcs, Way, and others 

 prove beyond cavil, that "with usual [or unusual] 

 falls of rain" no such quantity of ammonia is con- 

 veyed to the soil, as is here stated. We think 

 that Prof. Ilorsford will now admit that "ten (tons 

 of ordinary barn-yard manure contain more am- 

 monia than is carried to an acre of land in twelve 

 months by usual falls of rain." This fact greatly 

 weakens the force of Prof. Horsford's argument ; 

 but one object in quoting his remarks is not to at- 

 tempt to point out where they conflict with more 

 recent investigation?, but simply to show that Mr. 

 Lawes is not the only person who understood Lie- 

 big to teach "the mineral manure theory." 



"But if in the manure heap and the liquid accu- 

 mulations of the barn-yard, transported to the fields 

 the ammonia be not the chief ingredient, or an im- 

 portant one, tc*what are we to attribute the unques- 

 tioned value -of stable products and night soil % 

 Prof. Liebig has shown that if plants be manured 

 with the ashes of plants of the same species, as the 

 grasses of our western country are when burned 

 over in the fail, they are supplied with their na- 

 tural food. * * Let us consider what these ashes 

 are, and what manure is. Eerbivirous animals 

 ' derive their nourishment from the vegetable king- 

 dom exclusively, their food being grass, grain, 

 roots, etc. These, with their organic and inor- 

 ganic matters are eaten. A portion of them is 

 assimilated, becoming bone, muscle, tendon, fit, 

 etc. Another portion is voided in the form of ex- 

 crementitious matter. In process of time, the 

 bones and tissue follow the same course. What to- 

 day forms the eye, with its sulphur, and it's phos- 

 phorous, and carbon, etc., will have accomplished 

 it3 office, and left the organism to mingle with the 

 excrements or escape as carbonic acid ana water 

 from the lungs. At length ail ike inorganic mat- 

 ters will re-appear in the voided products. * * 

 The animal organism has performed the office of 

 a mill. Grain was supplied. Instead of appear- 

 ing as flour and bran and the intermediate meal, it 

 appears after intervals of greater or less length, 

 in soluble inorganic salts in the liquid excrements, 

 in soluble inorganic salts in the solid excrements, 



and in carbonic acid and water. Now, after burn- 

 ing a plant, what remains'? It contained when 

 growing carbon, nitrogen, hydrogen, and oxygen, 

 as organic bodies, and water. It contained also, 

 invariable proportions, common salt, potash, soda, 

 magnesia, lime, iron, phosphorous, sulphur, and . 

 silica. The first four were expelled in the com- 

 bustion. The remaining ingredients, for the most 

 part, remained unchanged. Had the plant gone 

 into the body of an animal, and in the coarse of 

 its evolutions through the organism lost its car- 

 bon, hydrogen, nitrogen, and oxygen, the remain- 

 ing ingredients would have been the same as be- 

 fore. In one case the plant would have been foam- 

 ed in the organism; in the other, in a crucible. 

 The ashes and the' excrements are substantially the 

 same. * * Night soil and guano are the aslies 

 of animal and vegetable organism burned in ani- 

 mal bodies. They are the ashes of plants — the 

 essential food of plants. Hence their value as ma- 

 nures.' 1 '' , 



We might multiply such quotations from 

 our agricultural literature of the past decade 

 ad libitum, but the above are sufficient to show 

 that Lawes and Wolf are not alone in ascrib- 

 ing the "pure mineral theory to Liebig." 



His pupils and followers, as well as those, 

 who differed with him, evidently understood 

 Liebig as asserting that if the inorganic consti- 

 tuents or ashes of a given species of plants 

 were supplied in sufficient quantity, and in 

 proper condition, we should obtain a maximum 

 yield ; that the crops on a field increased or 

 diminished as these mineral elements were sup- 

 plied or withheld ; that the mineral manure 

 patented by Prof. Liebig, was an embodiment 

 of his views ; and that "sooner or later, they 

 (farmers) must see that in this so-called 'mine- 

 ral theory,' in its development and ultimate 

 perfection, lie the whole future of agriculture.-' 



Liebig, in his recent pamphlet, denies ever 

 having entertained these views, and admits, 

 very reluctantly, however, that Mr. Lawes' ex- 

 periments prove them to be erroneous. He 

 now says : 



" I consider ammonia and its salts exceedingly 

 useful, and indeed at present oven, ■perfectly indis- 

 pensable as a means of increasing the produce "of 

 our fields beyond a certain limit, without the use 

 of stable manure." 



Surely there is some difference between this 

 sentence and the following one, which will be 

 found in the*first edition of Liebig's " Letters 

 on Chemistry," but which has been altered in 

 the subsequent edition, published since the ap- 

 pearance of Mr. Lawes' papers : 



"It follows consequently, that wo cannot i»- 

 crease the fertility of our fields by a supply ox ni- 

 trogenized manure, or by salts of ammonia ; but 

 rather that their produce increases or diminishes, 

 in a direct ratio with the supply of mineral ele- 

 ments capable of assimilation." 



It is evident from these and other sentences 



/ 



