_NATURAL HISTORY OF SELBORNE. II 
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 work 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.” 
