34 



TIMBER AND TIMBER TREES. [chap. 



very broad ones and numerous very narrow ones; 

 Chestnut, on the other hand, is easily distinguished from 

 Oak by having no broad rays. While the medullary rays 

 of the Willows, Poplars, and Hawthorn, etc., are colour- 

 less, those of the Elm, Birch, Alder, Beech, etc., are 

 pigmented.* 



Before converting or employing most kinds of woods, 

 particularly in dealing with unseasoned timber, it will be 

 necessary, for many purposes in carpentry, to regard 

 this arrangement of medullary rays, to ensure that the 

 work shall remain, when finished, free from warp or 

 twist upon the surface. The timber should be cut as 

 nearly as possible in the direction of these rays, the 

 shrinkage in seasoning being, for the most part, angular 

 to them. Workmen in general, and modellers in wood 

 in particular, endeavour to embrace the greatest length 

 of medullary figure in their work to guard against 

 warping, well knowing that if they do so it will stand 

 satisfactorily the test of time and wear. Others, who 

 are engaged in the cleaving of posts, rails, or palings for 

 park and other fences, know that they can only success- 

 fully do this by rending the piece in the direction of 

 these rays. It is by a careful study of this that we 

 obtain our best dnd most beautifully figured wainscot 

 from the slow-growing Oaks found in the North of 

 Europe, Austria, Asia Minor, and in some districts of 

 North America. 



By the mechanism of these medullary rays in inti- 

 mate connection with the annual layers, and chiefly in the 

 newly-formed wood, a means is afforded for the ascent 

 of water, containing traces of dissolved mineral salts, 

 such as potash, lime, common salt, etc., and gases, such 



* For other characters of the medullary rays see ' ' Timber and Some of its 

 Diseases " (Macmillan & Co. , 1890). 



