APPENDIX. 



291 



(3) Spring wood and summer wood, the former being the interior (first 

 formed wood of the year), the latter the exterior (last formed) part of 

 the ring. The proportion of each and the manner in which the one merges 

 into the other are sometimes used, but more frequently the manner in which 

 the pores appear distributed in either. 



(4) Pores, which are vessels cut thru, appearing as holes in cross-sec- 

 tion, in longitudinal section as channels, scratches, or identifications. (See 

 p. 23 and Figs. 129 and 130.) They appear only in the broad-leaved, so called, 

 hard woods; their relative size (large, medium, small, minute, and indis- 

 tinct when they cease to be visible individually by the naked eye) and man- 

 ner of distribution in the ring being of much importance, and especially in 

 the summer wood, where they appear singly, in groups, or short broken lines, 

 in continuous concentric, often wavy lines, or in radial branching lines. 



(5) Resin ducts (see p. 26 and Fig. 128) which appear very much like 

 pores in cross-section, namely, as holes or lighter or darker colored dots, but 



su.w.< :: 4 af::4. 



sp.w.\ 



11 



Fig-. 129. "King-porous" Woods White Oak and Hickory-. 

 a. r., annual ring-; su.~v., summer wood; sp.w., spring 

 wood; r, vessels or pores; c. /., "concentric" lines; rt, 

 darker tracts of hard fibers f rming the firm part of 

 oak wood;/r, pith rays. 



much more scattered. They occur only in coniferous woods, and their pres- 

 ence or absence, size, number, and distribution are an important distinction 

 in these woods. 



(6) Pith rays (see p. 21 and Figs. 129 and 130), which in cross-section 

 appear as radial lines, and in radial section as interrupted bands of varying 

 breadth, impart a peculiar luster to that section in some woods. They are 

 most readily visible with the naked eye or with a magnifier in the broad- 

 leaved woods. In coniferous woods they are usually so fine and closely 

 packed that to the casual observer they do not appear. Their breadth and 

 their greater or less distinctness are used as distinguishing marks, being 

 styled fine, broad, distinct, very distinct, conspicuous, and indistinct when 

 no longer visible by the naked (strong) eye. 



(7) Concentric lines, appearing in the summer wood of certain species 

 more or less distinct, resembling distantly the lines of pores but much 

 finer and not consisting of pores. (See Fig. 129.) 



