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 102 



small dendrites, from thence, is figured behind, and the 

 upper middle figure is one with the larger dendrites ; this 

 nearly resembles the darker Turkey Hone, or, which is much 

 the same, the Carpenter's Oil-stone, but is more stained 

 and blotched. It is, of course, sometimes found without 

 the dendrites ; but I figure it thus, to give one of its charac- 

 ters, and to exhibit a specimen of the sort of dendrites 

 which are supposed to be Manganese, and are sometimes 

 like stains upon the surface, as in the middle Jigure, and 

 sometimes run through the Stone in great variety, as in the 

 lack Jigure. Chorley Forest, in Lancashire, produces 

 a variety of Hones, or stones fit for sharpening tools, 

 which are called Chorley Hones. Indeed, there are vast 

 Varieties of stones used by the cutlers, according to the 

 coarseness or fineness of the grain ; and their distinctions 

 are all so essential, that it becomes of much consequence 

 to know the sorts for different uses, and the trade in them 

 is of great importance both abroad and at home. 



It is perhaps worthy of remark, that these stones may 

 be scraped with a knife, and give, generally, a light streak 

 like that of common Slate, although they will grind the 

 hard steel that will cut or scrape them. Schistose rocks 

 of many different compositions resemble wood. Perhaps, 

 from some of those usually called Turkey Hones resem- 

 bling wood, they have been thought to be petrified wood. I 

 am possessed of Schistose Rock from Devonshire, which 

 has been called Rotten-wood rock, from its resemblance to 

 rotten wood. I have, however, some petrified wood that 

 would nearly answer the purpose of a Hone, from Somer- 

 setshire, which shows the lateral fibre very distinctly, split- 

 ting with the usual longitudinal grain of the wood, and has 

 a slaty aspect. 



