88 AGRICULTURE 



the field, and, when the furrow slices had 

 sufficiently dried, the soil was carted to 

 certain points where it was piled in heaps, 

 interstratified with some kind of fuel (gener- 

 ally faggots), and slowly roasted or burned. 

 It was usually considered necessary to apply 

 from 50 to 100 tons to an acre, and the effects 

 were undoubtedly in many cases very 

 considerable. The present low prices of 

 agricultural produce, and the high rate of 

 wages, have combined to make clay burning 

 an obsolete process, and, moreover, the farmer 

 of to-day has a very much wider choice of 

 fertilizing materials than his predecessor of a 

 century ago. 



The results of burning clay, and applying 

 the material to the soil, may be summarized 

 as follows. Clay, to begin with, is hydrated 

 silicate of aluminium, and on account of its 

 being hydrated it is plastic and sticky, and, 

 under most conditions of weather, difficult 

 to work. But, in the process of roasting, 

 the water of combination is driven out, and 

 the substance left behind, while still a silicate 

 of aluminium, is no longer hydrated, and, 

 consequently, does not become sticky and 

 plastic when wet. The incorporation, there- 

 fore, of a large quantity of burned clay with 

 the natural soil of a field, produces a good 



