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V 



nourished, and that it took no necessary part in its organization. It was 

 found, however, that this inorganic part of the same plant was always of 

 the same kind of material, whatever was the character of soil upon 

 which it grew. This, evidently, would not have been the fact were its 

 presence wholly accidental, and not governed by some fixed laws. It 

 was also found that the composition of the ashes of different plants, 

 grown upon the same soil, varied much in the number and character of 

 their elements. It Avas further found that each kind of plant, in selectino- 

 for itself nearly a constant weight of inorganic matter, while it mio-ht 

 choose the same kind or kinds of earthy matters, that some other plants 

 do, to make up their composition, yet it was always in quantities peculiar 

 to itself. Thus, for example, wheat would contain eight pounds of lime 

 in every one hundred pounds of its ashes, while barley, in the same 

 weight of its ashes, would have only about four and one-half pounds. 



Different parts of the same plant have since been found, also, to have 

 different proportions of the same element — the ashes of the leaves differ- 

 ing in quantity and quality from those of the wood or body of the plant, 

 and both being different from the root or bulb. 



From the above facts it was inferred that the ingredients found in the 

 ashes of plants were essential constituents. This view was corroborated 

 by the observed fact, that plants will not thrive and come to maturity — 

 properly perfecting their seed, straw, &c. — in a soil destitute of the kinds 

 of matter usually found to be present in their ashes. 



These facts are the basis of a most important principle to the ao-ricul- 

 turist, and one that should be duly recognized, and fully understood by 

 every cultivator of the soil. Says Prof. Johnston, " It is difficult to 

 conceive the extent to which the admission of the essential nature and 

 constant quantity of the inorganic matter contained in plants, must 

 necessarily modify our notions, and regulate our practice in every branch 

 of aorriculture. It establishes a clear relation between the kind and 

 quality of the crop, and the nature and chemical composition of the soil 

 in Avhich it grows. It demonstrates what soils ought to contain, and, 

 therefore, how they are to be improved. It explains the effect of some 

 manures in permanently fertilizing, and of some crops in permanently 

 impoverishing the soil. It illustrates the action of mineral substances 

 upon the plant, and shows how it may be, and really is, in a certain 

 measure, fed by the dead earth. Over nearly all the operations of agri- 

 culture, it throws a new and unexpected light." 



