CONSTITUENTS OF PLANTS. 10/ 



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the ashes used as a manure, which is found to be 

 quite indispensable for the growth of the grain. 

 The soil itself, upon which the oats grow in this 

 district, consists of sandstone ; and although the 

 trees find in it a quantity of alkaline earths suffi- 

 cient for their own sustenance, yet in its ordinary 

 condition it is incapable of producing grain. 



The most decisive proof of the use of strong 

 manure was obtained at Bingen (a town on the 

 Rhine), where the produce and development of 

 vines were highly increased by manuring them 

 with such substances as shavings of horn, &c., 

 but after some years the formation of the wood 

 and leaves decreased to the great loss of the pos- 

 sessor, to such a degree, that he has long had 

 cause to regret his departure from the usual me- 

 thods. By the manure employed by him, the 

 vines had been too much hastened in their growth ; 

 in two or three years they had exhausted the 

 potash in the formation of their fruit, leaves, and 

 wood, so that none remained for the future crops, 

 his manure not having contained any potash. 



There are vineyards on the Rhine, the plants 

 of which are above a hundred years old, and all 

 of these have been cultivated by manuring them 

 with cow-dung, a manure containing a large pro- 

 portion of potash, although very little nitrogen. 

 All the potash, in fact, which is contained in the 

 food consumed by a cow is again immediately 

 discharged in its excrements. 



