MANURES. 137 



tion of the soil ; and such as increase the vigor and luxuriance 

 of plants by diminishing, modifying, or destroying substances 

 in the soil which are injurious to their growth. These classi- 

 fications, though from the nature of the subject necessarily 

 very imperfect, serve, nevertheless, to aid the inquirer in gain- 

 ing a knowledge of it, as well as the farmer and gardener in 

 the practical work of preparing and furnishing plant nutrition. 



The art of rightly applying manures to different soils, and 

 for the promotion of the growth of different plants, as well as 

 the neutralizing of noxious agencies, requires no small amount 

 of careful observation, experience, and skill. The herdsman 

 that should feed his oxen with beans, the shepherd that should 

 fodder his sheep with rye straw, or the groom that should feed 

 his master's favorite horse on swamp hay and onions, would be 

 laughed to scorn by every body but the cockney. Yet worse 

 blunders than these are continually made by such as are called 

 farmers. It is just as important that the farmer and gardener 

 should know how to feed their plants as their animals. It is 

 no more certain of your Indian corn, if it be only half fed, that 

 you will gather more than half a crop, than it is of your cow, if 

 treated thus, that she will yield more than half a mess of milk. So 

 of your other crops and animals ; they must all be fed with food 

 precisely suited to their wants, such as is best adapted to pro- 

 mote growth and maturity. It would seem, then, if the farmer 

 only knew how, that he might prepare his ground here for pro- 

 ducing wheat or any other grain or product suited to our 

 climate, and be almost as sure of a bountiful harvest as of a 

 seed time. 



The combinations of matter that enter into the organization 

 of plants are almost infinite, though the original elements are 

 few. Chemistry has discovered less than sixty elements in the 

 material world, called " simple substances," so named because 

 incapable of reduction. Of these, only four enter in any con- 

 siderable degree into the formation of plants — namely, carbon, 

 which forms from forty to fifty per cent, by weight of plant3 

 cultivated for food; oxygen, forming nearly one-half of the 

 crust of the globe, twenty-one per cent, of the atmosphere, 

 eight of every nine pounds of water, and nearly one-half of the 

 living organisms of plants and animals ; hydrogen, the lightest 



18* 



