AMERICAN INSTITUTE. 435 



be fit to undergo the operations of tillage far earlier and later 

 than undrained fields, and that manures produce twice the effect, 

 and last four times longer. Another wonderful advantage of 

 thorough drainage is, that air is admitted into the soil by an 

 underdraught through the chimneys of the drain. You all are 

 aware that air and water must be supplied to the roots, and if 

 you can give it to them as well below as above so much the bet- 

 ter. If you would be convinced of this, knock the bottoms of 

 your flower pots out, and compare the plants growing in them 

 with those in the one hole pot, and you will order five or 

 six holes made in all the pots you purchase afterwards. The 

 object of drainage as many suppose is not to deprive the soil of 

 moisture, but to regulate the quantity, and not drown the plant. 

 You will find that if the yearly increase of plants on undrained 

 land is five per cent., it will be on drained land ten per cent., and 

 on land drained firs.t and then irrigated twenty per cent. I have 

 heard farmers say that they did not believe in draining, that they 

 had not been successful, the reason was that they did not pay 

 attention to the regular inclination of their drains, instead 

 of having a uniform fall at the bottom, they left a rising in the 

 bed of the drain, where the descending water accumulated above 

 the level of the rising, causing stagnation, and destroying the 

 fall, the floor of the drains must be perfectly straight in their 

 descent to the outfiill. This can be easily accomplished by rods 

 such as I once before explained in the club as follows, to wit : 



" Take three staffs with cross pieces on the head, two of them 

 two feet long, and the third as much more than two feet as the 

 drain is deep, one of the short staffs is planted on the ground on 

 a level with the field at the head of the drain, and the other at 

 the lower end, the third is held in the drain, and as long as its 

 top is on a line with the other two the bottom is uniform.'' 



It is a remarkable fact that the evaporation from very wet land 

 is almost equal to the evaporation from water, the wetter the land 

 is then the greater the evaporation, and consequent excess of cold- 

 ness. Evaporation is less in the shade than in the sun; wet land 

 is warmest therefore in the shade. Persons suppose that an im- 

 mense amount of the water that fnlls during rain storms in a year 

 passes off' by filtration. This is a mistake, as only about five inches 

 of rain out of twenty-five inches that fall in a year percolate to 

 the depth of three feet. This would almost lead us to believe that 

 lands do not stand much need of drainage; but experience teaches 

 differently. It is well that it is so, as an excess of water produces 

 a corresponding diminution of the amount of air beneath the sur- 



