Q2 EDGE TOOLS. 



Tiepli/. W. N. 

 The fact that That razors and other fine-edged tools when dull, do recover 

 razor- Ac. re- ^ certain degree of sharpness after being kept for a time, has, 



cover tlieir t> . f or 



edge by laying I bclievc, been frequently noticed. I think the fact can scarce- 

 by, admittLd. j^ {^^ considered as doubtful ; but that it is requisite to strap 



the instrument in order to produce this acuteness, has not, that 



I know of, been before remarked. 

 The editor as- ^^Y former meditations on this phenomenon have induced 

 <:ribes ittooxi- nie to ascribe it to oxidation modified by a peculiarity in the 



rfntion and the . , t » • r ^i • t i i • 



peculiar uatiuo '^^^^^^ °' stcel. In the quarto series oi this Journal, vol. i. p» 

 of steel. 453^ I gave a short account of a Damascus sabre, with obser- 



Some account . , . , i i i- i • ^i^ .. i • j r 



of Damascus vations and experiments on the method ot making that kind ot 



^^^^^- stcel ; which has a wavy or fibrous appearance on its surface, 



called the water, and is valued for its rough cutting edge and 

 its tenacity. It was there explained that the water is produced 

 by the action of an acid upon the metal ; of which the minute 

 aggregate parts are some iron and some steel ; the former being 



Method of ex- more readily corroded than the latter. I likewise mentioned a 



amining tie nicthod I had, much to ray own profit and satisfaction, used 

 Tiniform tex- ' J i ' 



ture of steel by for ascertaining the texture of steel ; by applying diluted nitrous 



^" ^^' ' acid to its clear surface ; the elFcct of which is to shew the re- 



spective veins or imperfect mixtures of iron in the steel,— be- 

 cause these appear of a lighter colour than the steel itself, 

 which loads its solvent with plomb;ige or carburets of iron. 

 On the present occasion I must add, that I never found any 

 specimen, even of the finest cast steel, which did not exhibit 

 a very considerable mixture of parts, some more and some less 

 steely. 



All steel is pro- I strongly suspect that these facts may be applied to the case 



bably the same ]^f,f^^■^.Q ^g j ^yould assume the position, that the same irrciju- 

 as Damascus r ' r> 



steel, but fine larity which the acid shows us in steel, does also exist amons 

 ^'^"'^ ■ its very minute and perhaps invisible integrant parts ; or that all 



steel has the property of Damascus steel with regard to these- 

 parts. Whenever a razor is brought to a keen edge by grind- 

 ing, setting, and strapping, the fretting powders or the substance 

 on whicli it is thus rubbed convert it into a very fine toothed' 

 The fine teeth saw. By employing this edge against a soft substance the teeth 

 ?<i"e*^are'v«)rn ^'"^^ rubbed, down and the edge, though still thin, becomes muck 

 doHu by use; less qotched than before : the razor is then dull, and requires to 



be 



