96 AGBICULTUEE. 



the point of contact between the sponge and the water, and 

 this wetness will ascend up the sponge, in a diminishing 

 ratio, to the point where the forces of attraction and of 

 gravity are equal. This illustration is for gentlemen of 

 the Clubs, of London drawing-rooms, of the Inns of Court, 

 and for others of similar habits. For gentlemen who are 

 floriculturists, we have an illustration much more apposite 

 to the point which we are discussing. Take a flower-pot a 

 foot deep, filled with dry soil. Place it in a saucer con- 

 taining three inches of water. The first effect will be, that 

 the water will rise through the hole in the bottom of the 

 pot till the water which fills the interstices between the 

 soil is on a level with the water in the saucer. This effect 

 is by gravity. The upper surface of this water is our 

 water-table. From it water will ascend by attraction 

 through the whole body of soil till moisture is apparent at 

 the surface. Put in your soil at 60, a reasonable summer 

 heat for nine inches in depth, your water at 47, the seven 

 inches' temperature of Mr. Parkes's undrained bog; the 

 attracted water will ascend at 47, and will diligently occupy 

 itself in attempting to reduce the 60 soil to its own tem- 

 perature. Moreover, no sooner will the soil hold water of 

 attraction, than evaporation will begin to carry it off, and 

 will produce the cold consequent thereon. This evaporated 

 water will be replaced by water of attraction at 47, and 

 this double cooling process will go on till all the water in 

 the water-table is exhausted. Supply water to the saucer 

 as fast as it disappears, and then the process will be perpe- 

 tual. The system of saucer-watering is reprobated by every 

 intelligent gardener ; it is found by experience to chill 

 vegetation ; besides which, scarcely any cultivated plant 

 can dip its roots into stagnant water with impunity. Ex- 

 actly the process which we have described in the flowe,r- 

 pot is constantly in operation on an uridraiued retentive 

 soil : the water-table may not be within nine inches of the 

 surface, but in very many instances it is within a foot or 

 eighteen inches, at which level the cold surplus oozes into 



