On Manures. 219 



land should be immediately laid down to grass. In many 

 soils, more especially when newly cultivated, calcareous earths 

 will, in the course of years, so far disappear, as to require a re- 

 newal. This sooner or later takes place in all cases, but more 

 rapidly in pastures than in arable land, the plough often bring- 

 ing up the lime to the surface. 



10. Difference between Caustic and Mild Lime. This is a 

 point that has not hitherto been sufficiently attended to, and 

 yet, unless it is well understood, lime may often be misapplied. 

 The following hints, extracted from a paper written by an 

 intelligent agriculturist (* a3 ), will throw some light on this 

 important inquiry. 



Lime, when newly burnt, is of a caustic nature, and of- 

 ten retains that quality longer than is commonly imagined. If 

 applied to dead, but undecayed vegetables, it shrivels them 

 up, and destroys their organization ; it may be used, there- 

 fore, with great advantage, for the destruction of weeds in fal- 

 lows. It may be advantageously employed in all cases where 

 there is a great abundance of vegetable matter; but where 

 the soil is deficient in nutritious substances, mild lime ought 

 to be preferred. Caustic lime is said to exhaust the land, be- 

 cause it hastens the putrefaction of the animal and vegetable 

 matter in the soil, and thus a larger portion of them is applied 

 to the growth of plants, in a given space of time, than would 

 otherwise have been the case. In this manner, it first pro- 

 duces more luxuriant crops, and in the next place, it enables 

 the farmer to continue his land in tillage, until it is more com- 

 pletely deprived of the principles of fertility, than could have 

 been practicable, if the calcareous manure had not been used. 

 Caustic lime is of so burning a quality, that the dung of horses, 

 dropped round a lime-kiln, is so completely destroyed, either 

 by that which falls from the carts in filling, or the particles 

 blown about by the wind, as to become absolutely useless. It 

 is not fit, therefore, to be employed with dung when in that 

 state. If quick-lime is used with a crop of potatoes, the 

 sets are corroded by it, and the crop rendered curled and 

 scabbed. When lime, in a caustic state, is applied to land, it 

 is of service by destroying acidity ; but it exhausts the soil of 

 the carbonic acid, or fixed air, which it contains. It is of great 

 use in composts, (as shall be afterwards explained) ; but dung 

 should not be mixed with caustic lime, nor with animal ma- 

 nures, unless they are too rich, or to prevent any noxious ef- 

 fluvia, as in the case of night soil. 



Mild lime, on the other hand, may often be applied with 

 advantage, when caustic lime would be injurious ; and more 



