REPI.ACEMENT OF EXHAUSTED ALKALIES. "5 



The woodcutters in the vicinity of Heidelberg have the privi- 

 lege of cultivating the soil for their own use, after felling the 

 trees used for making tan. Before sowing the land thus obtained, 

 the branches, roots, and leaves, are in every case burned, and 

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

 sable for the growth of the grain. The soil itself upon which 

 the oaks grow in this district consists of sandstone ; and although 

 the trees find in it a quantity of alkaline earths sufficient for 

 their own sustenance, yet in its ordinary condition it is incapable 

 of producing cereal crops. 



The most decisive proof of the use of strong manure was ob- 

 tained at Bingen (a town on the Rhine), where the produce and 

 development of vines were highly increased by manuring them 

 with such nitrogenous manures as shavings of horn, &c. ; but 

 after some years the formation of the wood and leaves decreased 

 to the great loss of the proprietor, to such a degree that he has 

 long had cause to regret his departure from the usual methods, 

 ascertained by long experience to be the best. 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 re- 

 mained 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 

 proportion of alkaline ingredients, although very little nitrogen. 

 All the alkalies, in fact, contained in the food consumed by a 

 cow are again immediately discharged in the liquid excrements. 



The leaves and small branches of trees contain the greatest 

 quantity of ashes and of alkalies ; and the quantity of them annu- 

 ally removed from a wood, for the purpose of being employed as 

 litter,* contain much more of the alkalies than all the old wood 



* [This refers to a custom some time since very prevalent in Germany, 

 although now discontinued. The leaves and small twigs of trees were 

 gleaned from the forests by poor people, for the purpose of being used as 

 litter for their cattle. The trees, however, were found to suffer so much 

 in consequence, that their removal is now strictly prohibited. The cause 

 of the injury was that stated in the text. — Ed.] 



