78 



THE BOOK OF THE ROSE 



CHAP. 



insisted) those minerals with the addition of nitrogen 

 would, in the proper proportions, make real, though 

 artificially made, manure. They first of all discovered 

 the component parts of a plant by burning it and 

 analysing the ashes, and they then said (and proved it), 

 These are the things of which the plant is made, and 

 therefore with these things it can be fed. They found 

 next that the different parts of a plant, roots, stem, 

 leaves and flowers, often had the principal constituents 

 in very different proportions, but this could be allowed 

 for in considering which part of the plant is most 

 valuable. The obvious next step was to analyse the 

 soil too, and it was found that some of the mineral con- 

 stituents of plants are practically present in sufficient 

 quantities in nearly all soils, but that some land is 

 deficient in one material, and some in another. A 

 pleasing picture was then presented to the cultivator, 

 that, with the analyses before him of his own soil and of 

 the plant he intended to grow, it was comparatively easy 

 to see just how much he required of each mineral con- 

 stituent to feed his plants fully and perfectly. 



But analysis of soil was found to be a very different 

 thing from that of a plant; you cannot adulterate 

 a plant or put anything into its frame which the roots 

 will not naturally take up ; thus all plants of the same 

 species or variety would analyse alike, but very few 

 samples of soil from the same field would agree together. 

 The analysis is necessarily minute, and takes account of 

 everything ; the droppings of a bird or tiny animal may 

 have rested on the spot for a while and added some 

 fertile elements, or just that portion may have been im- 

 poverished of one or more special items by the roots of 

 a plant or weed which is no longer present. Only a 

 rough estimate therefore of the general fertility of a soil 



