CULTIVATING MACHINERY. The soil contains both mineral and organic matter. The more clay there is in a soil, the heavier, stiffer or more plastic it is and the more difficult to work; the more sand, the lighter or more friable or crumbly it is, and the easier to work. An important property of clay is its power to absorb and retain moisture ; sand on the other hand is unretentive of moisture. Different soils, therefore, require different treatment according to the climatic conditions and the crops to be grown. The objects of cultivation are briefly, (I ) to produce a good tilth, i.e., that condition of the soil which will best assist the germina tion of the seed and its root development and subsequent plant growth; (2) to add humus (organic matter) and fertilizers to the soil in order to provide food for the growing plant; (3) to destroy and prevent the growth of weeds which would otherwise compete with the crops for living room and food; (4) to modify the con dition of the soil so as to regulate the amount of moisture, the temperature and the access of air. All these operations may be performed by the aid of specially devised implements.