EFFECTS PRODUCED BY PLANTS ON THE SOIL. 97 



or any apparent falling off, and congratulates himself upon 

 the possession of a farm of inexhaustible fertility. Such is the 

 case at present in many of the newly settled states, the soils 

 of which are supposed by their cultivators to possess some 

 peculiar qualities difterent from those of the old world. But 

 the same thing was observed in the tobacco lands of the early 

 settled southern states, where we are told wheat and tobacco 

 were produced in succession, without manure, for upwards of 

 a hundred years ; but at last a time arrived when these lands 

 would scarcely return the seed, and the same thing must happen 

 in the other states if the same injudicious system be pursued. 

 Formerly in the plantations of our West Indian colonies, sugar 

 could be produced without any necessity for manuring the 

 sugai'-cane plantations, but at present that is impossible, and 

 the planters are obliged to send to this country and to Eng- 

 land for the materials which their exhausted fields require, 

 or, as is done in some settlements, remove to other districts 

 where the soil has been less mjured. Now the so-called vir- 

 gin fields of North America are not difterent in composition 

 from what the soils of Ireland were, at the time they were first 

 broken up by the plough. Waving forests once covered our 

 hills, and their remains for centuries enriched the soil with 

 mineral ingredients, but as population increased, om* husband- 

 men, like the fanners of Virginia, grew upon them crop after 

 crop of scourging grain, and fed upon them flocks of cattle 

 which were exported to other countries without any return 

 being made for the thousands of tons of materials thus taken 

 away. But our farmers did not know that in their crops and 

 cattle they were selling the materials of their fields, nor was 

 the planter in British Guiana until lately aware, when he 

 burned the crushed sugar-canes and threw away the ashes, 

 that they were capable of supplying to his soils nearly all 

 the ingredients which the crop had withdrawn from them. 



140. The soil, you have seen, is produced either by the 

 crumbling down of the bed of rock upon which it rests, or by 

 the materials transported by water from other parts of the 

 country. It can contain only the mineral substances of which 

 the rocks are composed, and some of the most important of 

 these, we have seen, exist in exceedingly minute quantities, and 

 being by decomposition rendered soluble in water, may be carried 

 away by the action of rain. At all events, the available stock 

 of materials ui even the best soils being limited, a time must 



