NATURAL HISTORY OF SELBORNE. 11 



large quantities cannot be procured but at considerable expense. 

 Among the blue rags turn up some blocks tinged with a stain of 

 yellow or rust colour, which seem to be nearly as lasting as the 

 blue ; and every now and then balls of a friable substance, like 

 rust of iron, called rust balls. 



In Wolmer Forest I see but one sort of stone, called by the 

 workmen sand, or forest-stone. This is generally of the colour of 

 rusty iron, and might probably be worked as iron ore ; is very hard 

 and heavy, and of a firm, compact texture, and composed of a 

 small roundish crystalline grit, cemented together by a brown, 

 terrene, ferruginous matter ; will not cut without difficulty, nor 

 easily strike fire with steel. Being often found in broad flat pieces, 

 it makes good pavement for paths about houses, never becoming 

 slippery in frost or rain ; is excellent for dry walls, and is sometimes 

 used in buildings. In many parts of that waste it lies scattered on 

 the surface of the ground ; but is dug on Weaver's Down, a vast 

 hill on the eastern verge of that forest, where the pits are shallow 

 and the stratum thin. This stone is imperishable. 



From a notion of rendering their wore the more elegant, and 

 giving it a finish, masons chip this stone into small fragments 

 about the size of the head of a large nail, and then stick the pieces 

 into the wet mortar along the joints of their freestone walls ; this 

 embellishment carries an odd appearance, and has occasioned 

 strangers sometimes to ask us pleasantly, "whether we fastened 

 our walls together with tenpenny nails." 



