8 NxVTURAL HISTORY OF SELBORNE. 
with the horizon, and therefore should not be surbedded, but 
laid in the same position that it grows in the quarry.* On the 
ground abroad this fire-stone will not succeed for pavements, 
because, probably, some degree of saltness prevailing within it, 
the rain tears the slabs to pieces. t Though this stone is too hard 
to be acted on by vinegar ; yet both the white part, and even the 
blue rag, ferment strongly in mineral acids. Though the white 
stone will not bear wet, yet in every quarry at intervals there are 
thin strata of blue rag, which resist rain and frost ; and are ex- 
cellent for pitching of stables, paths, and courts, and for building 
of dry walls against banks (a valuable species of fencing, much 
in use in this village), and for mending of roads. This rag is 
rugged and stubborn, and will not hew to a smooth face ; but is 
very durable : yet, as these strata are shallow and lie deep, 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 nor 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 
* To surbed stone is to set it edgewise, contrary to the posture it had in the quarrj', says Dr. 
Plot, Oxfordsh. p. 7", But surbedding does not succeed in our dry walls ; neither do we use it 
so m ovens, though he says it is best for Teynton stone. 
t " Firestone is full of salts, and has no sulphur: must be close grained, and have no inter- 
stices. Nothing supports fire like salts* saltstone perishes tKposed to wet and frost.'* Plot's 
Su\r. p. 152. 
