Laboratory Equipment. 



379 



be obtained in section cutting without sharp knives and razors. An oil- 

 stone should therefore be provided, and a fine hone and strop for razors. 1 

 To sharpen an ordinary pocket knife, hold the under face of the blade at 

 an angle of about ten degrees with the stone, and impart a sliding back 

 and forth motion, honing the two sides alternately until a keen edge is 

 produced, keeping 

 the stone well oiled 

 with mineral oil. 



The razor should 

 be kept in such con- 

 dition that at any 

 place on its edge it 

 will readily cut in 

 two a hair held be- 

 tween the thumb and 



FIG. 203. 



Showing how to draw a razor over the 

 stone in honing it. 



forefinger. If it will 

 not do this, it may 

 only need stropping on the prepared leather of the strop. To tell 

 whether it should be honed on the stone before stropping, moisten 

 the ball of the thumb and pass it with gentle pressure longitudinally 

 along the edge of the razor ; if the edge, throughout its length, produces 



the sensation of tak- 

 ing hold of the skin, 

 the use of the stone 

 will not be necessary, 

 but otherwise the 

 razor should be 

 honed on the oil- 

 stone until it re- 

 sponds properly to 

 the test. In honing, 



FIG. 204. 

 Showing how to draw a razor over the strop. 



oil the stone with 

 mineral oil ; hold the blade of the razor flat on the stone and slide it 

 edge foremost along the full length of the stone, imparting a longitudi- 

 nal as well as a forward motion to the razor, so that it glides for its full 

 length from point to heel over the stone, as shown in Fig. 203. Then 

 turn the razor on its back, so that the other side lies on the stone, and 

 slide the razor forward and longitudinally, edge foremost, as before. 



1 One of the best for this purpose is the Torrey combination strop and hone. 



