MANUS A HAND. IOI 



the whole seventeen only three will require our careful 

 attention. Let us examine them again, and 'endeavor 

 to understand this matter. It is not half so difficult 

 as it appears at first sight ; and when we once get at 

 the facts, experiment will easily show us what to do 

 with every kind of soil. 



Oxygen, we remember, is a gas. It is abundant in 

 the air and in the water, and, combined with other 

 elements, forms the larger part of every soil, however 

 rich, however poor. As it is in water and in air, and 

 as it is ever eager to unite with other elements in the 

 soil, all we have to do is to give the air and water a 

 chance. Tillage settles that. The plough, the hoe, 

 the harrow, the spade, and the rake invite the oxygen 

 to come in and be at home in the soil. So we have 

 not to think about the oxygen. There will always be 

 oxygen in every soil, even without tillage ; and with 

 tillage there will be more than enough for every crop. 

 It is the same with carbon and hydrogen. They are 

 abundant in the air ; and though these three, oxygen, 

 carbon, and hydrogen, form the larger part of every 

 plant, we need not concern ourselves about them, 

 because every plant in a well-tilled soil, if well supplied 

 with water, will find more than it wants of each. Of 

 course we must keep in mind, all the time, that none 

 of the fourteen elements are used by the plants in a 

 pure state. All are combined in some way with others 

 in every soil. 



The silicon, sulphur, chlorine, sodium, magnesium, 

 aluminium, iron, manganese, iodine, and fluorine can 



