PREPARING AND HANDLING FERTILIZERS, 161 



largely of quick lime, and contains more or less sulphate 

 of lime (gypsum or plaster), formed by the conversion of 

 the dangerous sulphide into sulphate of lime. It may 

 be used after exposure to mix with muck, but cannot 

 safely be used in its fresh state. It is an easy matter to 

 expose it before adding it to the muck, and thus be on 

 the safe side. 



BURNING CLAY AND SODS. 



Burning clay for manurial purposes, is an old fashion, 

 which deserves renewed notice and practice. Along with 

 the clay or with ordinary soil or swamp muck, may be 

 mingled coarse sods, the scrapings of road-side ditches, 



Fig. 191. BURNING CLAY AND SODS. 



the mossy surface and hard tussocks of swamp meadows, 

 rough " waste wood," coarse weeds, and other similar 

 matters which slowly decay, and are of no value until 

 they are decomposed. These combustible matters are 

 placed in small heaps over an old meadow, which needs 

 renewal, or any other piece of land. The rough waste 

 matters being gathered, placed, and covered with earth, 

 so that they will burn slowly, in the manner shown in 

 figure 191; care being taken to so arrange them, as to 

 distribute the heat all through the mass and the earth 

 with which it is covered. These heaps are fired and left 

 to burn slowly for several days, when the dust and ashes 



