MAKING SECTIONS OF WOOD, ETC. 



339 



so that the thinnest possible slice may be taken off by the 

 knife ; after a few thick slices have been removed to make the 

 surface level, a small quantity of water or spirit may be placed 

 upon it, the screw is then to be turned one or more divisions, 

 and the knife passed over the wood, until a slice is cut off; 

 this, if well wetted, will not curl up, but will adhere to the 

 knife, from which it may be removed by pressing blotting 

 paper upon it, or by sliding it off upon a piece of glass by 

 means of a wetted finger; the plan the author generally 

 adopts, is to have a vessel of water by the side of the machine, 

 and to place every section in it ; those that are thin can then 

 be easily separated from the thick by their floating more 

 readily in the water, and aU that are good, and not imme- 

 diately wanted, may be put away in bottles with spirit 

 and water, and preserved for future examination. If the 

 entire structure of any exogenous wood is required to be 

 examined, the sections must be made in at least three 

 different ways; these may be termed the transverse, the 

 longitudinal, and the tangental, or, as they are sometimes 

 called, the horizontal, vertical, and tangental; each of these 

 will exhibit different appearances, as may be seen by D E F 

 in fig. 226. At A is shown part of the stem of a coniferous 



ABC 



Fig. 226. 



:e £ 



plant, and a transverse section of a portion of the same mag- 



22* 



