84 ANNUAL OF SCIENTIFIC DISCOVERY. 



of food, as animals can ; consequently, provision must be made for bringing 

 constant supplies to them. The rain that falls into the porous soil dissolves 

 the saline and ammonieal matters it finds there, and flows with its load 

 through the rootlets into the interior of vegetable structures. Air takes up 

 carbonaceous substance of the nature of charcoal into a sort of gaseous 

 solution, and then is blown by every puff of wind into the open mouths that 

 gape upon the surfaces of vegetable leaves. Of water and saline, ammonia- 

 cal, and carbonaceous substances, all vegetable bodies are composed. A di- 

 lute solution of the fixed and ammoniacal salts is sucked up by the roots. 

 An abundance of leaves is then pushed forth, and carbon drunk in by their 

 myriad mouths. Xo other demand is made of the soil than a sufficient 

 supply of saline and ammoniacal substances, and water enough for their 

 solution and transport. 



In order that the soil may be able to furnish these requisite matters, it is 

 essential, in the first place, that it should have them ready for use in its sub- 

 stance; and in the second place, that its texture should be so loose and 

 porous, that both water and growing roots may find an easy passage through 

 it. In the old practice of farming, the strength of the soil was kept up by 

 burying in it saline, ammoniacal, and carbonaceous matters, mixed indis- 

 criminately together. So soon as Liebig had shown that the great propor- 

 tion of the carbon found its way into the plant through the leaf, and not 

 through the root, it was seen that there was great want of economy in the 

 proceeding. "\Vhcn farm-yard manure is ploughed into the land, tons upon 

 tons of carbonaceous substance arc placed beneath the surface, which can 

 effect nothing else there but their own escape from a useless position. 

 Hence, the custom was slowly introduced of using only concentrated saline 

 and ammoniacal manures, in the stead of the more bulky product of the 

 straw-yard. Now a refinement upon even this refinement is advised. Pro- 

 fessor Way says that the soil requires no manuring at all during many 

 years, and that ultimately it will need only a slight dressing of saline mate- 

 rials. He has discovered that it can keep itself rich in ammonia. Clay is, 

 according to his views, mainly composed of a series of ingredients that have 

 the power of attracting this volatile and pungent body continuously from 

 the air.* The ammoniacal constituents of vegetable nutrition are therefore 

 given to the soil by the air, just as the carbonaceous constituents are to the 

 leaves. The atmosphere is the grand reservoir of nourishment, and the soil 

 plays a very subordinate part indeed. Out of its substance, nothing else is 

 contributed than the very trifling proportion of saline or earthy matter that 

 remains in the form of ash after any vegetable structure has been submitted 

 to the process of burning. Even the poorest soils contain within themselves 

 saline ingredients for multiplied crops of the richest kinds of grain. 



It follows, from these data, that the only requirements in a good seed-bed 

 are, that it shall be a layer of loosened and finely comminuted earth, which 

 has been well turned over in the process of preparation. Break up the soil 

 thoroughly, and open out its substance to the air, and it will maintain its own 

 productiveness through lengthened years. In the first place, it will con- 

 stantly throw more and more of its reserved bullion into active circulation; 

 and in the second place, it will keep a sufficient quantity of floating capital 

 always within call for the safe transaction of affairs. If Professor Way's 



* These compounds are called, in the language of the chemists, double silicates 

 of alumina and potash alumina and soda, and alumina and lime. 



