108 THE MAGAZINE OF HORTICULTURE. 



in spring — say three inches in depth, within one foot of the 

 top of the ground. Roots of plants go down lower than this, 

 if the soil is mellow and not flooded with water. 



"Mr. Dalton's experiments, made with a cylindrical vessel, 

 ten inches in diameter, three feet deep, filled with gravel, 

 sand and soil — having a discharge pipe at the bottom, by 

 which to measure the quantity of water that rims off, and 

 which gave perfect drainage — the top of the soil being cov- 

 ered with grass, the whole buried so that the top was even 

 with the ground, shows that earth that is moderately moist 

 will take up three inches of water without carrying it beyond 

 the point of saturation. This amount had in the preceding 

 dry month been taken up by the plants and evaporated, and, 

 without making the soil too dry, had so drawn upon it that 

 it could imbibe three inches, which fell in four days. 



"Ordinary ploughing does not bring into use more than 

 six inches in depth of soil ; extraordinary ploughing may 

 reach as low as one foot. Subsoiling and trenching to the 

 depth of three feet would give to the plants all that Mr. 

 Dalton claims for his experiments. 



" Where ground is cultivated only six inches deep, it only 

 holds, subject to the purposes of vegetation, (if no account is 

 made of water rising up through the hard earth beneath,) 

 one inch and a half of water. If cultivation goes down one 

 foot, the quantity of available water is doubled. If the soil 

 is broken up still deeper, though it may be that the roots of 

 the plants may not go down beyond a foot, yet the water 

 from lower down will rise up by capillary attraction, and 

 supply the evaporation from the superior parts of the soil. 

 So it results that while one foot of earth will hold, for the 

 uses of vegetation, three inches'of water, three feet will hold 

 so much that it can part (without becoming too dry) with 

 three inches, and then receive, in the course of a four days' 

 rain, another three inches, without overflow, or discharging 

 from the drains beneath. 



" A soil that holds no water for the use of plants below 

 six inches, will suffer from drought in ten days in June, July 

 or August. If the soil is in suitable condition to hold water 



