ON THE PRINCIPLES OF ARTIFICIAL MANURING. 133 



no extension and g-ravity, no effect can be produced, no 

 burden raised. 



Guided by experience, which is the fundamental basis of 

 all inductive science, and Avhich teaches us that for every 

 etiect there is a cause, that every quality — as, for instance, 

 the fertility of a field, the nourishing- quality of a vegetable, 

 or the effect of a manure — is intimately connected with and 

 occasioned by something- which can be ascertained by weig-ht 

 and measure, modern science has succeeded in enlightening- 

 us on the cause of the fertility of the fields, and on the 

 efiects which are exercised on them by manure. 



Chemistry has shown that these properties are produced 

 by the composition of the fiekls ; that their fitness for pro- 

 ducing- wheat or some other kind of plants bears a direct 

 proportion to certain elements contained in the soil, which 

 are absorbed by the plants. It has likewise shown that two 

 fields, of unecjual fertility, contain luiequal quantities of these 

 elements : or that a fertile soil contains them in a different 

 form or state from another which is less fertile. If the 

 elements are contained in the soils in sufficient quantities, it 

 produces a rich crop : if it is defective in one of them only, 

 this is shown very soon, by the impossibility of g-rowing- in it 

 certain kinds of plants. 



Moreover, it has been proved with certainty what relations 

 these elements of the soil bear to the development of the 

 plants. Chemical analj'sis has demonstrated that a certain 

 class of these elements is contained in the seeds ; others, in 

 different proportions, in the leaves, roots, tubers, and stalks. 

 They are mineral substances, and, as such, are indestructible 

 by fire, and consequently remain as ashes after the incinera- 

 tion of the plants or of their parts. ]Many of these elements 

 are soluble in pure water, others only in water containing' 

 carbonic acid, as rain water ; all were absorbed from the soil 

 by the roots of the plants in a dissolved condition. It has 

 been shown that, if in a field those elements which remain 

 after the incineration of the g-rain or seeds are present in an 

 insufficient quantity, no wheat, no barle}"", no peas — in a 

 word, none of those plants can be cultivated on that field, 

 •which are grown on account of their seeds. The plants 

 which grow on such a field produce stalks and leaves ; they 

 blossom, but do not bear fruit. The same has been observed 

 regarding- the development of leaves, roots, and tubers, and 

 the mineral elements which they leave behind after their 

 incineration. If, in a soil in which turnips or potatoes are to 



