Accessory Apparatus 253 



shapes of knife (A, B, C, Fig. 71) require their own special 

 blade-holders ; these should be purchased with the knives 

 to save subsequent annoyance. 



The Hone. — It is of the utmost importance to secure a 

 good hone, which should have its upper surface about 9 by 

 2 inches, and commonly about an inch thick. A hone 

 answering well enough for common razors may not be of 

 much use for microtome knives. Some hones have their 

 sharpening surface altogether too hard. The surface should 

 be of exceedingly fine grain, and so soft that it may be easy 

 to scratch it with a pin. Of course, this test should not 

 be applied to the sharpening surface, but at the side. The 

 yellow Belgian hone, the German razor hone, and the 

 Turkey hone are those from which a suitable one may be 

 selected. One worth having will cost in the size indicated 

 about sixteen shillings. The German razor hone is obtained 

 from Eatisbon, in Bavaria, where it is found in the slate 

 mountains, forming yellow veins in the blue slate. The 

 Turkey hone is obtained under similar conditions from 

 Asia Minor. The yellow vein is commonly cut into slabs ; 

 these are secured to pieces of slate to give them strength 

 and solidity. Or one may procure a hone so cut from the 

 formation that the under part runs into the slate, and the 

 upper yellow sharpening surface into the vein. It may 

 interest readers to know that a collection of various sharpen- 

 ing stones is to be found in the Jermyn Street Museum of 

 Geology, London, W. 



Process of Sharpening. — Sperm-oil may be used on 

 the hone as the lubricant, but it is more advantageous 

 to use water and soap. One may make a lather of 

 the best palm-oil soap with which to freely anoint the 

 hone, or a fine stream of water may be allowed to flow 

 continuously over the hone, and a piece of palm-oil soap 

 rubbed frequently over its surface. With care, a knife 

 will only require honing at remote periods, but if one has 

 to cut hard substances which turn the edge of the knife 

 the hone will be in daily demand. The hone must be 



