542 EXHAUSTION NATUKALLT PREVENTED. 



spread in ; the lines of wheat are a yard asunder, and catch all the rain 

 or dew that descends upon them ; and thus half an acre of heavy clay 

 land brings six or seven quarters of Beans, or twenty-seven tons of 

 Swedish Turnips; and would carry Carrots, Cabbages, Celery, and 

 Onions, in similar proportion if it were a kitchen garden. 



It may be added, that by a similar process were obtained some 

 magnificent British Gueen Strawberries, exhibited a few years ago, at 

 Chiswick, by the Speaker of the House of Commons, which the spec- 

 tators fancied that the right honourable gentleman must have raised by 

 excessive doses of guano. 



Under natural circumstances exhaustion is provided against 

 by the decay of plants where they stand, the soil thus receiving 

 back from the dead not only what it yielded up to the living, 

 but as much more as the living were able to solidify at the 

 expense of the atmosphere. And hence the extraordinary 

 fertility of the soil of some virgin countries. When nature 

 causes the tree to shed its leaves, it is not merely because they 

 are dead and useless to the tree, but because they are required 

 for a further purpose — ^that of restoring to the soil the principal 

 portion of what had been abstracted from it during the season 

 of growth, and thus of rendering the soil able to maintain the 

 vegetation of a succeeding year. Every particle that is found 

 in a dead leaf is capable, when decayed, of entering into new 

 combinations, and of again rising into a tree for the purpose 

 of contributing to the production of more leaves, and flowers 

 and fruit. If the dead leaves, which nature employs, are re- 

 moved, the soil will, doubtless, upon the return of spring, 

 furnish more organizable matter without their assistance; 

 because its fertility is difficult to exhaust, and many years 

 must elapse before it is reduced to sterility. But the less we 

 rob the soil of the perishing members of vegetation which 

 furnish the means of annually renewing its fertility, the more 

 wiU our trees and bushes thrive; for the dead leaves of 

 autumn are the organic elements out of which the leaves of 

 summer are to be restored in the mysterious laboratory of 

 vegetation. They contain the carbon or humus, and the 

 alkaline substances essential to the support of growing plants ; 

 and although such substances can be obtained from the soil, 

 even if leaves are abstracted, yet they can never be so well 

 obtained as through the decay of those organs. 



