Forms of Lime.--There is unnecessary confusion in the mind of the public regarding the forms of lime that should be used. If amounts greatly in excess of needs were being applied, the form would be a matter of concern. There would arise the question of soil injury that might result from the use of the lime in caustic form. Again, if pulverized limestone were used, a very heavy application would bring up the question of coarseness in order that waste by leaching might be escaped. Most farms needing lime do not have cheap supplies, and the consideration is to secure soil alkalinity at a cost that will not be excessive. Freight rates and the cost of hauling to the fields, added to first cost of the lime, limit applications on most farms to the necessities of a single crop-rotation which includes clover, or, at the most, to two crop-rotations. Under these circumstances it is best to let cost of correction of soil acidity determine the form of lime to be used. The material that will render the soil friendly to clover for the least money is the right one to select. We need to be concerned only with the relative efficiencies of the various forms of lime, as measured in terms of money. That which will most cheaply restore heavy clover growths to the land is the form of lime to be desired. The contentions of salesmen may well be disregarded as they produce confusion and delay a work that is important to the farmer. Definitions.--The use of the various forms of lime will become general, and the terms employed to designate them should be understood. They vary in their content of acid-correcting material, and their correct names should be used with accuracy. _Stone-lime_, often called lump-lime or unslaked lime, or calcium oxide or CaO, is a form widely known, and may be taken as a standard. It is the ordinary lime of commerce, and is obtained by the burning of limestone. One hundred pounds of pure limestone will produce 56 pounds of stone-lime (CaO). _Pulverized lime_, often called ground lime, is stone-lime after being pulverized to permit even distribution. When it is fully exposed to the air or moisture, it slakes and doubles in volume. _Hydrated lime_, often called slaked lime, is a combination of stone-lime and water. The water causes an increase in weight of 32 per cent, 56 pounds of stone-lime becoming 74 pounds of the hydrate. _Pulverized limestone_, often called carbonate of lime, is the unburned limestone made fine so that good distribution may be possible. _Air-slaked lime_, often called carbonate of lime, is stone-lime or hydrated lime combined with carbonic acid from the air, and thereby increased in weight. Fifty-six pounds of stone-lime, or 74 pounds of hydrated lime, become 100 pounds of air-slaked lime.