240 



J. B. LAWES AND JUSTUS VON LIEBIG. 



^.yalue as a fertilizer." In other words, drawing olf 

 the ammonia of manure does not decrease its fertili- 

 zing value. 



. Dr. Wessenisosx, writing from AV'eimar to the 

 jj.Lpndon Farmers' Magazine, vol. 15, 373, says : 

 , " Ilie great rule of Prof. Liebio's new system of 

 manuring is the following: Let the fields not be ma- 

 nured with stable dung, nor with any sort of dung 

 ^.whatever that contains organic (vegetable or animal) 

 ^.substances along with its inorganic (mineral) prinoi- 

 __ pies. This mineral manure the farmer has to procure 

 _^ pither by mcinorating all the vegetable substances 

 , ^j that he has reaped, and which he cannot profitably 

 ..J sell or consume on his farm, especially by burning 

 ^ the straw; or by apitlying to a chemist with a view 

 ,)iof hfx[ing both the soil to be manured and the ashes 

 „tof plants to be cultivated duly analysed, and of get- 

 •(fting prepared, conformably to the result of such an- 

 .(j.alyses, an artificial manure (mineral manure — manure 

 ^pi ashes) containing the very mineral food that the 

 -.plant wants, and that is not already contained in the 

 ^ground. * « * Xhe farmer saves (by the new 

 j(, system of manuring) almost the whole of the expen- 

 ^ diture for transporting manure to the fields, as the 

 ^.weight of the mineral manure he wants is only 2.G 

 ' .ft.per cent, of that of the stable dung hitherto used." 

 •_,j , In one of his lectures, Mr. Kaekeck adverted " to 

 the doctrine recently introduced by Prof Liebio, 

 jphich under-estimated the influence of organic ma- 

 pures in the soil and attached the more importance 

 • to the inorganic constituents of plants, by keeping a 

 vppply of which in the soil, he is of opinion that the 

 prbon and nitrogen which are necessary for the 

 growth of plants u'ill be supplied through the atmos- 

 phere. This is a theory altogether opposed to the 

 experiments which he (Mr. Kahkeck) had placed be- 

 fore them that day, and it was also opposed to Lie- 

 ' '"big's previous teaching." — Far., Mag, vol. xv. 2G0. 

 Prof E. N. IIoKSFOED, while with Prof Liebig 

 , at Geissan, will be considered good authority in re- 

 gard to the views of Liebig on this point. In a let- 

 ter to Prof. Webster, dated Geissen, May 1, 1S46, 

 * he says: "You are aware that Boussinoault has ex- 

 . pressed the opinion, after a variety of experiment?, 

 , that the value of manure is ui near relation to its 

 percentage of ammonia. Mclder has, you know, 

 Jj;%ritten much in support of the view that ulmic and 

 *»" humic acids, ulmates, humatcs, etc., in one form and 

 J" another, minister largely to vegetation. * * Lie- 

 big dilfers from them all. * * He takes the po- 

 '^\ sition that the sources of carbon and nitrogen are 

 •'"'carbonic acid and ammonia in the air. * * * 



" It is obvious (from analyses of soils and rain-wa- 

 ter) that the ammonia spread on fields in the ordina- 

 ry distribution of barn-yard products is of no mo- 

 ment. The quantity with usual falls of rain greatly 

 exeeeds, in the course of a season, any conceivable 

 supply by human instrumentality. » * * 



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

 lations of the barn-yard, transported to the fields, 

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

 portant one, to 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 

 fall, they are supplied with their natural food. * * 

 Let us consic'cr what these ashes are, and what ma- 

 nure is. Hirbivorous animals derive their nourish- 

 ment fro;;i the vegetable kingdom exclusively, their 

 food being grass, grain, roots, etc. These, with their 

 orgauic and inorganic matters are eaten. A portion 

 of them is assimilated, becoming bone, muscle, ten- 

 don, fat, etc. Another portion is voided in the form 

 of excrementitious matter. In process of time, the 

 bones and tissue follow the same course. What to- 

 day forms the eye, with its sulphur, and its phospho- 

 rous, and carbon, etc., will have accomplished its 

 office, and left the organism to mingle with the ex- 

 crements, or escape as carbonic acid and water from 

 the lungs. At length all the inorganic matters ivili 

 re-appear in the voided products. * * The ani- 

 mal organism has performed the office of a mill 

 Grain was supplied. Instead of appearing as floui 

 and bran and the intermediate meal, it appears aftei 

 intervals of greater 'or less length, in soluble inor 

 ganic salts in the liquid excrements, in insoluble in 

 organic salts in the solid excrements, and in carbon 

 ic acid and water. Now, after burning a plant, wha 

 remains? It contained when growing carbon, nitro 

 gen, hydrogen, and oxygen, as organic bodie.s, an( 

 water. It contained also, in variable proportions 

 common salt, potash, soda, magnesia, lime, iron, phos 

 phorous, sulphur, and silica. The first four were ea 

 pelled in the combustion. The remaining iugrodienta 

 for the most part, remained unchanged. Had thil 

 plant gone into the body of an animal, and in th) 

 course of its evolutions through the organism lost iti 

 carbon, hydrogen, nitrogen, and oxygen, the remain 

 ing ingredients would have been the same as before 

 In one case the plant would have been burned in th 

 organism; in the other, in a crucible. The ashB' 

 and the excrements are substantially the same. * '■ 

 Night soil and guano are the ashes of animal an< 



