OF SELROTvlS^K. l? 



quarry.* On the ground abroad this fire- 

 stone 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 w^hite part, and even the blue rag, fer- 

 ments strongly in mineral acids. Though 

 the w^hite 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 build- 

 ing of dry walls against banks ; a valu- 

 able species of fencing, much in use in 

 this village, and for mending of roads. 



* To surbed stone is to set it edgewise, contrary to 

 the posture it had in the quarry, says Dr. Plot, Ox- 

 fordsh. 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 Teynlon stone. 



t " Firestone is full of salts, and has no sulphur :> 

 " must be close-grained, and have no interstices. No- 

 " thing supports fire like salts ; saltstone perishes ex- 



posed to wet and frost." PMs Staff, p. 152. 

 VOL. I. C 



