gg BOARD OF AGRICULTURE. 



To understand this, let it be borne in mind that drains, how- 

 ever deep and frequent, can never take from the soil (such soils 

 as we are considering) an}' amount of water which is necessary 

 for vegetation, for all will retain enough, and stiff clays more 

 than enough, by capillary attraction. This capillary attraction 

 is the power which enables a sponge to absorb and retain 

 moisture. Take a piece of dry sponge and weigh it ; now wet it 

 thoroughly, and after allowing all the water which will pass oflT 

 by its own weight to do so, weigh it again, and we find it much 

 heavier than before ; now e.xpel as much as possible of the water 

 by pressure, still it is heavier, showing that water is yet re- 

 tained by some active and powerful agency. This is a fair 

 illustration of capillary attraction, a power which acts in direct 

 opposition to that of gravity. The weight of the water in the 

 soil, or its gravity, is the only power which sends it to the 

 drains, consequently only the excess can be thus carried away. 

 To illustrate farther, let a barrel be filled witli dry, loamy earth, 

 and after adding water (a measured quantity) to saturation, tap 

 it at the bottom, and see how much can be thus drawn off; we 

 find that after it ceases to run, a considerable portion is retained, 

 the earth is still as moist as is needful for the germination of 

 seeds or the growth of plants. (Before the barrel is laid aside, 

 pour some liquid manure from the drainings of the barnyard 

 into it, and thus illustrate another fact relative to the subject, 

 which is, the power of drained land to absorb and hold on to 

 manure, allowing only water to pass away.) Try still another 

 experiment: fill the barrel again with dry earth, leaving the 

 hole in the bottom, and set it in a tub or puddle of water; grad- 

 ually you find the water ascending, by the force of capillary 

 attraction, until the whole is moist. 



Wc are now ready to inquire, why do plants suffer from 

 drought, and the answer is, obviously, because the roots do not 

 penetrate deep enough to find moisture, for there is always 

 water enough in the soil, if the roots could only reach it, and if 

 it be asked, why they do not thus penetrate, one grand reason 

 will be found to be, that they soon come to the water table, that 

 is, the level of cold stagnant water in the soil ; and cold water, 

 however excellent in its place, yet stagnant in the soil, is as 

 effectual a barrier to vegetation as would bo a layer ©f any 



