300 On burning Clay for Manure. 



When cool, the ashes thus produced are fit for use, and 

 may be put on clay land in tne same manner as wood 

 ashes, and will have an astonishing effect in producing 

 prodigious crops of either grass, grain, or any vegetable.' ' 

 In the 14th volume of the Bath Soc. Memoirs, the 

 Rev. W. Wilkieson also gives an account of his experi- 

 ments on burning clay. The soil was a cold, stiff, tena- 

 cious clay, that had been over cropped for a series of 

 years. He marked out a space of fifteen by twelve feet, 

 excavated it one foot deep, and with the soil thrown out 

 made a wall round the space. At each corner he made 

 an air pipe, each pipe (made of sods) extending only two 

 feet into the enclosure, in a diagonal direction. In the 

 centre of the enclosure, he placed upright the but end 

 of a large tree, around which other fuel was placed, co- 

 vering the bottom of the whole space within the wall. 

 Dry turf was placed over the whole surface, which was 

 again covered with a thin coat of clay, except a small 

 hole by which the fire was introduced. The fire spread 

 rapidly, and it required the exertions of two men to smo- 

 ther the flames as they burst out. During the first two 

 or three days, the surface of the heap occasionally sunk 

 in places, and apparently grew cold ; into these places 

 fresh fuel was put, care being taken to make small open- 

 ings, and that the operation be done as speedily as possi- 

 ble ; for external air let into the heaps, seems to do mis- 

 chief. Each covering of clay crumbled to ashes in an 

 hour or two after it was put on. The heap was on fire 

 twelve days, and was attended by two men : one was 

 chiefly employed in digging the clay ; the other in wheel- 

 ing it to the heap and throwing it on, sometimes by hand, 

 and sometimes with a spade. The ashes were tried as a 



