THE PRINCIPLES OF ARTIFICIAL MANURING. 



69 



THE PRINCIPLES OF ARTIFICIAL MANURING. 



(Second Fart.) 

 BY PROFSSSOR JUSTUS LIEBIG. 



Twenty-five years ago, when the manu- 

 facture of spa and mineral waters began, 

 they met with violent opposition from the 

 members of the Faculty, as being deprived of 

 all the good quahties of the natural ones — as 

 wanting, in a certain conditio, sine qua nan 

 — in a spiritus rector, or vital power, which 

 alone gave them any medicinal qualities. 

 Those times have passed now — Chemistrj' has 

 demonsti-ated to a certainty what the con- 

 stituents of those vaiious waters are, and un- 

 der what forms and compounds they are 

 united in them. It has succeeded in cora- 

 bming them exactly m the same propor- 

 tions, and in rendering them not only equal 

 to the natural ones, but even more effective. 

 Only from that time physicians were induced 

 to connect certain effects on the human body 

 with certain elements in the waters, and were 

 enabled by the light of Science to add more 

 of this element, or more of that ; nay, to ap- 

 ply, instead of the waters themselves, the one 

 active element alone, as is, for instance, the 

 case with iodine in indurations and struma. 

 It is well known that at this moment there are 

 extensive maiuilkctiu-es of mineral waters in 

 England, at Berlin, at Dresden, at Vienna, etc. 



Now, I beUeve that the same principle 

 may be applied, partially, at least, to the use 

 of manufactured manures, which, ui England, 

 has just been called into existence. Guano, 

 that powerfiil manure, the efficacy of which, 

 in a jvidicious application, has been clearly 

 demonstrated by the testimony of the most 

 uitelligent farmers, cannot be su{)plied for a 

 much longer period, because the rich stores 

 in Cliili and Africa must be shortly exhausted. 

 As it is only in veiy dry countries that it is 

 found, we camiot expect to discover many 

 more places containing it, and what are we 

 then to do ? My attention has often been di- 

 rected to the question whethei", according to 

 our experience and the present state of Sci- 

 ence, a manure might not be composed which 

 could replace the genuine guano in its effects, 

 iuid whether I could not, by a series of ex- 

 periments, point out a way of pre[)aring one 

 equal tt) it in all its chemical and physical 

 properties ? You are well aware that we know 

 with certainty all the elements of the guano, 

 as well as the urine and solid feces of men 

 and iuiimals. in like maimer it seems to have 

 verilied the ophiion vvliich I have laid down 

 in my work on Agriculture, that the siilts 

 manufactured in tlie laboratoiy have the same 

 effect on the growth of plants if they are em- 

 bodied to the fields, in the same fonns in 

 which the animals furnish them in their ex- 

 (165) 



crements. This must be evident to every 

 one who knows that to produce these com- 

 pounds in the laboratory, the same agencies 

 and means are made use of which are em- 

 ployed by Nature. The fabrication of a ma- 

 nm-e, equal in its composition and effects to 

 the solid and fluid excrements of animals and 

 men, seems to me one of the most essential 

 demands of our time — more especially for a 

 country like England, in which, from various 

 circumstances, a rational Agriculture without 

 a supply of manure, in some shape or other, 

 from icithout, seems nearly impossible. Our 

 reasoning will appear the more correct if we 

 remember how different are the results which 

 have been obtained by the different analyses 

 of the different sorts of guano — how little the 

 farmer can depend upon producing from a 

 given quantity a certain effect, as the latter 

 naturally varies according to the composition 

 of the foiTner. There are scarcely any two 

 samples in the market with the same compo- 

 sition — nay, not even similar. The following 

 salts may be regarded as the essential con- 

 stituents of a powerful manure applicable to 

 all descriptions of soil : 



Earthy Phosphates. — -The most important 

 of these is Phospluite of Lime, which occm's 

 in nature as a mmeral called apatite. It is 

 the principal component m bones, which, it 

 may be observed, have been found most effi- 

 cacious if calcined, consequently deprived of 

 then- animal matter. The rapidity of the ef- 

 fects of phosphate of lime on the growth of 

 plants depends upon its greater or lesser solu- 

 bility. Its amount of glue (gelatine) dimin- 

 ishes this solubility if the soil is rich in veget- 

 able matters, which furnish carbonic acid by 

 their decomposition, and which acid is re- 

 quired for rendering the phosphate of lime 

 soluble in water, and uiti-oducing it uito the 

 organism of the plants. In the calcined state 

 the bones act sufficiently quickly ; but in 

 those soils in wliich this cause of solubility is 

 wanting their action is slower. In my work 

 I had recommended the addition of a certain 

 (luantity of sulphuric acid, both in order to 

 render the boues more soluble, and to change 

 the neutr;il phospliate of the bones into gyp- 

 sum, and into a pho.sj)hate which contains 

 niQre acid — supei-])hos[)iiate of lime. I have 

 been informed tli;it this advice has been most 

 extensively adopted, tluit the supcrpho.<phate 

 of lime has been found to be a most effica- 

 cious manure, and that it forms already a most 

 important article ofConunerce. A second 

 eartiiy phosphate, not less impoi-taut, is the 

 Phosphate of Magnesia, which it is well 



