CHAPTER I. 



PROPERTIES OF WOOD.* 



A. ANATOMY OF WOOD, ITS STRUCTURE AND TEXTURE; 

 IDENTIFICATION OF WOODS. 



THE elementary organs of which wood is constructed are 

 the chief means of identifying woods ; their combination, as 

 seen in various sections, at once strikes the eye. Variations 

 in the physical and technical properties of woods, e.g., in a 

 piece of oak as compared with a piece of spruce, also depend 

 chiefly on their anatomical structure. We cannot, however, 

 explain all the physical and technical differences in woods by 

 a microscopical examination of their anatomy. Tin- micro- 

 scope does not indicate, or indicates very incompletely, the 

 materials that determine durability of timber; it gives no 

 information regarding brittleness or elasticity, nor how the 

 ultimate components of the wood are arranged or react on 

 one another. Anatomy tells us nothing about the myci'llar 

 and molecular structure of the cell-walls, the etl'ucts of which 

 on the chemical, physical and technical properties of wood 

 are still very obscure. But anatomy is indispensable in 

 elucidating vital processes in the physiology of trees, in 

 explaining the processes of the formation and decay of timber. 



Microscopes are seldom necessary for identifying woods, 

 all the characters that follow 7 being recognizable by the 

 naked eye. In the following plates, prepared for the new 

 (icrman edition of Gayer's book, structural items are repro- 

 duced in their natural size, the microscopic plates of the 

 earlier editions having been suppressed. ! 



Nature has facilitated greatly the study of the structure of 



* "Lasiett's Timber and Timber Trees," edited by Marshall Ward. 1S1H; 

 " Wood," G-. 8. I'.oulyer. l'.t(2 -. "The Timbers of Commerce," fferbert Stone, P.i'H ; 

 Kx|iloit;itinii CumiiHTCKilr .!-; BoiB," Mathey. P.M.MJ. 



| The translator has, however, retained these plates to illustrate the inicro- 

 BCOpic account of wood-structure given further on. 



