620 SELECTIONS FROM ADDRESSES. 



ing a southern aspect are much warmer than those sloping 

 towards the north. By selecting southern slopes, we may, 

 even here, obtain the climate of South Carolina. Much of the 

 success of a New England farmer, in raising corn profitably, 

 will depend on the judicious selection of those portions of his 

 farm where the highest temperature can be obtained. The 

 coldest portions may be devoted to oats, the intermediate por- 

 tions to wheat, barley and potatoes ; but corn loves a high 

 temperature, and should always be planted where this condi- 

 tion can be most perfectly fulfilled. 



2d. The temperature of the soil may also be increased by 

 thorough drainage. While water remains in the soil, evapora- 

 tion goes on at all temperatures. You know that when water 

 passes from a liquid state to vapor, it is because the heat ab- 

 sorbed by the water overcomes the mutual attraction of its 

 particles, driving them asunder until they become vapor. No 

 portion of the heat thus employed is sensible to the thermom- 

 eter ; it is therefore called latent heat. It is found by experi- 

 ment, that just 1,000 times as much heat is rendered latent by 

 the vaporization of water, as would raise the temperature of 

 the liquid water just one degree. It is easy to see that a con- 

 stant evaporation of the stagnant water, resting on the imper- 

 vious subsoil, must carry off an enormous amount of sensible 

 heat, or, in other words, it must keep the surface too cold for 

 the profitable growth of Indian corn. Underdraining and sub- 

 soil ploughing will enable the farmer to plant from a week to 

 a fortnight earlier, germination is effected more perfectly, the 

 roots have a greater range for procuring food, it is less affected 

 by drought, and insures a temperature better fitted to promote 

 the chemical transformations necessary for the tissues of the 

 plant, than could be obtained while the water rests on the 

 subsoil. 



3d. There is another mode of increasing the temperature of 

 a' soil, which maybe practised under certain circumstances, 

 that is, by changing the color of the soil. Black surfaces 

 absorb much more heat than light colors, as is well known to 

 every school boy. If powdered charcoal is sprinkled on a cold 

 soil, by absorbing the sun's rays it conveys much heat to the 

 soil, besides operating usefully as a manure. 



11. A sufficient amount of moisture is essential to the 



