54 



Burning Land for Manure. 



mately blended together, in which case the theory of the action 

 of the water, and mixing the soil into mortar, becomes explicable 

 in the following manner, viz. — when burned without mixing, the 

 finer particles of soil are apt to be acted on by the fire ; but when 

 coarser matters become intimately mixed with the finer portions 

 of the clay, the fire is not sufficiently strong to vitrify the coarser 

 parts, although hot enough to flux the same when finely divided — 

 otherwise Mr. Long's experiments would be quite in opposition 

 to the daily practice of the brick, tile, and earthenware manu- 

 facturers, who water and tread their clays for the express purpose 

 of rendering the same into a firm hard mass when baked. With 

 a few remarks respecting another class of stiff soils, viz. marls, I 

 shall conclude this part of the subject. Marls that contain a 

 moderate amount of vegetable matter, and a considerable quantity 

 of lime, will be found to burn easily in moderately dry weather, 

 by being formed into heaps in the ordinary manner, viz. by 

 heaping the pared sods into masses about four or five yards' dis- 

 tance from each other, and applying fire to the same. If, how- 

 ever, the marl consists of a tough blue character, so frequently 

 found as a subsoil, and in a great measure destitute of organic 

 matter, any attempt to burn the same for manure other than in 

 a kiln will be found fruitless, and for this purpose small coal 

 should always be used. This description of marl will generally 

 be found the most advantageous soil to burn for manure, but the 

 greatest caution is required in conducting the operation. If the 

 same, from inattention, want of knowledge, or other cause, is found 

 overburned or baked, it will generally be found that an applica- 

 tion of cold water to the lumps will speedily disintegrate them. 



Sandy soils should never be burned, except as a cleaning 

 operation : the same remark applies to gravelly soils. On both 

 the system to be pursued should merely consist of repeated 

 ploughings, harrowings, &c., and raking up the weeds and other 

 waste vegetable matters, and applying fire to them. In proportion 

 as soils proceed from stiff clays and marls, or rather from alumi- 

 nous to silicious soils, will the benefit to be derived from burning 

 soils be found to diminish ; whilst the stiffer the soil, the greater 

 the benefit. The 7ie plus ultra of burning a stiff soil is when 

 ashes are obtained of a deep red colour if the oxide of iron is 

 present, and in small rounded lumps that easily crumble into 

 a fine powder when pressed between the fingers, possessing a 

 gritty feel : such ashes will be found to possess every mechanical 

 advantage and all the beneficial chemical changes which fire is 

 capable of giving to soils. Deep vegetable soils, as bogs and 

 peat-mosses, are greatly benefited by paring and burning, for 

 which purpose the land should be pared by the breast or push 



