The agricultural revolution which swept the country during the second half of the 18th Century, with new forms of crop rotation and methods of soil improvement to increase yields, led to the use of lime as a fertiliser. In areas of the country such as North Northumberland, where limestone is the predominant rock, the limestone was burned in small kilns for use locally. Remains of these kilns, often mistaken for ruinsed defensive towers, can frequently be seen in the countryside between here and the Scottish border.
