14 Mr. Knight on the Means of giving 



less, but always at a very acute angle, by raising'the back of 

 the razor more or less, proportionate to the strength which I 

 wish to give to the edge; and I move the razor in a succession 

 of small circles from heel to point, and back again, without 

 any more pressure than the weight of the blade gives, till my 

 object is attained. If the razor have been properly ground 

 and prepared, a very fine edge will be given in a few seconds; 

 and it may be renewed again, during a very long period, wholly 

 by the same means. I have had the same razor, by way of 

 experiment, in constant use during more than two years and a 

 half; and no visible portion of its metal has, within that pe- 

 riod, been worn away, though the edge has remained as fine 

 as I conceive possible ; and I have never, at any one time, 

 spent a quarter of a minute in setting it. The excessive 

 smoothness of the edge of razors thus set led me to fear that it 

 would be indolent, comparatively with the serrated edge given 

 by the strop ; but this has not in any degree occurred ; and 

 therefore I conceive it to be of a kind admirably adapted for 

 surgical purposes, particularly as any requisite degree of 

 strength may be given with great precision. Before using a 

 razor after it has been set, I simply clean it on the palm of 

 my hand, and warm it by dipping it into warm water ; but I 

 think the instrument recommended operates best when the 

 temperature of the blade has been previously raised by the aid 

 of warm water. 



A steel bar, of the cylindrical form above described, is, I 

 think, much superior to that of a plane surface for giving a 

 fine edge to a razor or penknife ; but it is ill calculated to give 

 a fine point to a lancet ; and I therefore cause a plane surface 

 to be made, a quarter of an inch wide, on one side of the bar, 

 by cutting away a part of its substance ; and I have found 

 this form to be most extensively useful. 



The edge of some razors, whether formed of wootz, of mixed 

 metals, or of pure steel, but particularly of mixed metals, has 

 generally appeared to me to be more keen and active when 

 used a few seconds after it had been applied to the bar, than 

 on the following day ; and I have often seen the utmost activity 

 restored to the edge of such instruments, so instantaneously, 

 and by so apparently inadequate means, that I have been 



