Farm Buildings and Cottages. 

 Materials. 



213 



Materials for making concrete (apart from lime and cement) 

 are so numerous, varied, and generally abundant, that I shall 

 only mention the principal. 



Pit gravel (large and small), sand, and shingle with sand, are, 

 no doubt, the best ; next to these I shall place debris removed 

 from old buildings, in the shape of broken tiles, bricks, and 

 stone, not omitting the old mortar ; after these come any kind 

 of stone that can be easily broken up, slag from furnaces, and 

 ashes of all kinds ; lastly, when the above materials cannot easily 

 be obtained in sufficiently large quantities, I should use hard 

 burnt clay ballast, which, if mixed with some of the harder kinds 

 of material just enumerated, would also make a good concrete. 



Lime. — Limestone of various qualities is found nearly all 

 over the country ; the most suitable for concrete purposes are the 

 poorer limes, that burnt from claystone being the best. Lime 

 is easy of manufacture, and, where stone is procurable and coal 

 moderately cheap, is not expensive ; it can be burnt by any 



Fig. 1. — Common Lime-hiln. 



, ■ A. Arched opening for lighting kiln and drawing lime. 



B. Stone wall lined with fire-brick. 

 c. Layers of limestone separated by layers of coal 

 D. Covering of large stones to keep in the heat. 



farm labourer, after a little instruction, in the simple open kiln. 

 Fig. 1 represents a section of a common open limekiln filled 

 with limestone ready for burning, the thick black lines indi- 

 cating the layers of coal ; the opening A is the fire-hole.* 



Lime for making concrete is best if ground by machinery to 



* See also Mr. C. Turner's Prize Essay on " Ordinary and Improved Kilns for 

 Burning Lime for Agricultural Purposes," ' Journal of the Koyal Agricultural 

 Society,' 2nd series, vol. vii., p. 132. 



