256 Modern Microscopy 



with a razor. After a few such applications of sperm-oil, 

 drying and shaving, the strop is placed aside for a few days 

 to dry, when it will be ready to receive the sharpening 

 paste, which the writer has found to suit his purpose ex- 

 tremely well, and of which particulars will follow. Mean- 

 while the leather surface may be examined carefully in 

 order to find the direction of the grain of the leather. When 

 found, an arrow should be engraved on the wood each side 

 of the strop, pointing in the direction of the grain, not 

 against the grain. The knife should be worked in the 

 direction of the arrow, consequently with the grain, not 

 against it, and the arrows will facilitate this. 



From these remarks it will be observed that, as there 

 can be only one direction of grain, each side of the knife 

 will have a side of the strop retained for its use, and 

 in changing the sides of the knife the strop must be 

 reversed. 



Strop Paste. The paste with which the strop is now 

 charged is made as follows : 



Diamantine No. 2, about 0*1 gramme, mixed upon a glass 

 slab with the smallest possible quantity of sperm-oil. 



Diamantine is a very fine white powder used by polishers, 

 and made by A. Guyot-Lupold, Locle, Switzerland. It can 

 be obtained in this country at jewellers' tool supply stores. 

 A J-ounce bottle will last for years. 



Stropping the Knives. The mixture is thinly spread 

 over the surface of the strop and rubbed in with the palm 

 of the hand, stroking in the direction of the grain. The 

 writer has tried many other polishing powders, but has 

 always obtained the best results in 'the manner above 

 indicated. The beginner is cautioned not to use too 

 much of the powder, in the vain hope of putting an 

 edge to the knife by a few strokes upon the strop. The 

 surface of the strop will not be hard and glistening by 

 this treatment, after the manner of the strop recom- 

 mended for razors ; its surface will be dull and soft, and 

 will improve with use if its surface is not hacked, so that 



