OF SELBOBNE, 
11 
and runs by tlie intense heat, and so cases over tlie whole 
face of the kiln with a strong vitrified coat like glass, that 
it is well preserved from injuries of weather, and endures 
thirty or forty years. When chiselled smooth, it makes 
elegant fronts for houses, equal in colour and grain to the 
Bath stone ; and superior in one respect, that, when sea- 
soned, it does not scale. Decent chimney-pieces are worked 
from it of much closer and finer grain than Portland ; and 
rooms are floored with it ; but it proves rather too soft for 
this purpose. It is a freestone, cutting in all directions ; 
yet has something of a grain parallel 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 firestone will not succeed for pavements, be- 
cause, probably, some degree of saltness prevailing within 
it, the rain tears the slabs to pieces.^ 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 excellent 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 ex- 
pense. 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 
^ " To surbed stone is to set it edgewise, contrary to the posture it 
had in the quarry," says Dr. Plot, Oxfordsh. p. 77. But surbedding 
does not succeed in our dry walls ; neither do we use it so in ovens, 
though he says it is best for Teynton stone. — Gr. W. 
2 Firestone is full of salts, and has no sulphur : must be close- 
grained, and have no interstices. Nothing supports fire hke salts ; salt- 
stone perishes exposed to wet and frost. — Plofs Staff', p. 152. G. W. 
