5 8 AGRICULTURE. [CH. 



manure to be capable of performing. We may now 

 proceed to notice how the caustic lime can be most 

 economically and advantageously enabled to perform 

 these duties. 



in. It has been already explained that some of 

 these duties can only be accomplished by lime when 

 caustic. In such cases the lime should be brought 

 into work with the least possible loss of its causticity. 

 You are already aware of the fact that the carbonic 

 acid of the atmosphere has a strong disposition to 

 combine with the caustic lime, and in doing so the 

 lime loses its caustic character and becomes a car- 

 bonate of lime. As a rule, much of the lime used as 

 manure is allowed to be exposed to the weather to a 

 very great extent, before it is able to commence its 

 work. 



112. There are two methods by which caustic lime 

 is slaked. One of these is a bad and wasteful 

 system and the other is a good and economical 

 plan. It is a too common practice for lime which has 

 been drawn for manure, to be distributed over the land 

 in small heaps, and left there until the rain has slaked 

 it. This not only leads to much delay, but, as the 

 slaking takes place gradually, much of the lime has 

 been acted upon by the carbonic acid of the atmos- 

 phere, and much of its power lost before it is brought 

 into use. Compare with this the care taken by a 

 mason when slaking lime for mortar: no delay is 

 allowed, it is done quickly by adding sufficient water, 

 and then it is heaped up and covered from the air by 

 sand. Some farmers adopt the same plan, and as soon 

 as the heaps are made in the field, a water cart carries 

 round the water required for the proper slaking of the 

 lime, and it is then heaped up, and protected from the 

 air by a covering of earth. For building purposes it 

 is necessary to slake the lime thoroughly and without 

 loss, and it is equally so for use as a manure. The 

 only difference is that the loss is more easily detected 



