I'LANTIXG. 



An examination of many different kinds of wood proves that these 

 characters of distinction ure constant, and, therefore, afford acertain means 

 of distinguishing; the wood or timber of one species of tree from that of 

 another. 



The follow ins: discriminating' characters of the woods of the principal 

 timber trees will he found constant: 



The wood of the elm (fig. (i) is distinguished by having 1 the medullary 

 . or silver grain, equal, and not crowded. The concentric layers are 

 composed of a series of cells of nearly unequal diameter, arranged in an 

 almost simple curved line. The spaces between the layers are furnished 

 \\ith cells of a smaller diameter, and rather thinly scattered over the 

 surface. 



The oak (Jig. V) has two series of medullary rays; the primary ones 

 arc large and strongly marked, distant from each other, and are uninter- 

 rupted in their course from the pith to the bark (Jig. 6, 1). The secondary 

 ia\s are numerous between the primary, but not crowded. 



"The concentric layers, or circles, are distinguished by the arrangement 

 of the cells. They are grouped in somewhat triangular masses, forming 

 a \\avy circular outline. The structure of the concentric layers or annual 

 ring>, distinguish at once with certainty the wood of the oak from that of 

 the chestnut, with which it has often been confounded. 



The wood of the ash (r) has the places of those rays so prominent on 

 the wood of the oak, supplied by twin rays(l) placed in wide intervals over 

 the surface, and between these double rays are smaller ones, placed in 

 ular order. In the narrow spaces between the individuals which con- 

 stitute the twin rays are wanting those apparent remains of the cellular 

 texture \\hicli are so remarkable in the spaces between the single rays. 



, 



w 



d f tin- beech (</) has the | rimary ra\s (:>) dispersed pretty 

 ily oxer ihe surface of a Imri/ontal section of the wood; the secon- 

 ding lays are net continuous from the pith to the bark, but interrupted, 



