138 INDUSTRIAL USES OF WOOD. 



are used, but the wood for sounding-boards is of a special 

 kind. For this only coniferous wood is used, chiefly spruce, more 

 rarely silver-fir. 



The simple anatomical construction of sprucewood and the 

 absence of vessels, the extremely fine evenly distributed medullary 

 rays, the straight and long-fibred nature of the wood, and above 

 all its uniform structure, render it most suitable of all woods 

 for reverberating pure tones. Such wood must have narrow 

 and uniform annual zones, must have no knots, contain Httle 

 resin, be straight-fibred and of low specific gravity, 0*40 to 0*45. 

 The best wood for musical instruments should have zones 

 between 1"5 and 2 mm., and the summer- wood | to -jl- of 

 the zone. 



Trees producing such wood grow in mountain-regions at 

 altitudes between 2,500 and 4,500 feet above sea-level, on cool 

 and not too fertile localities. They are generally grown in 

 selection forests, where the trees get little room for development, 

 until they are middle-aged, but more room as old trees. 



Certain forest districts in Bavaria, ]:{ohemia and the French 

 Jura, are renowned for the production of this wood, also Galicia 

 and North America. The trees are sawn into quarters, and then 

 along the radius, into planks | inch thick ; they are then 

 seasoned, planed, and sorted according to their tones. 



Recently, attempts have been made to produce such wood 

 artificially by glueing together thin veneers of wood by means 

 of turpentine, shellac, gum, Sec, and pressing it into planks. 



Straight-grained beechwood in planks Ih inches thick is largely 

 used for pianos, being cut along the radius, which prevents its 

 warping as much as ordinary beechwood. 



Many foreign woods are used for piano-cases — ebony, maho- 

 gany, American walnut, sycamore, &c., and Florida-cedar for the 

 hammers. Woods similar to those in use for pianos are also 

 employed in organ-building. 



Venetian blinds and shutters use up much light wood, especially 

 spruce, and wood of similar quality to that used for sounding- 

 boards is used for the better sorts of blinds, much of it coming 

 from Bavaria. 



