OF MICROSCOPIC OBJECTS. 



145 



The edge of this saw I charge with diamond-powder. To 

 the edge of the saw I hold my specimen, and as it cuts I 

 lubricate the edge 1 with a small brush dipped in turpentine. 



With this method I have cut sections of fossil wood so thin 

 that all its structure has been well defined and required 

 nothing but mounting in balsam; this has been silicated 

 fossil wood. In cutting calcareous fossil wood, I have to 

 cut the sections thicker and grind them down. My grinding 

 apparatus is composed of leaden laps, which I make to 

 revolve in a horizontal position on the same upright spindle 



