44 OF WOOD IN GENERAL. 



Exposure to air or light darkens the colour of most wood, as is 

 well seen in freshly felled, as compared to seasoned, Mahogany. 

 Moisture carries this darkening deeper into the wood, whilst the 

 black of Oak and the dark brown of Yew after prolonged immer- 

 sion in bogs are well known. The translucency of all sound 

 timber when in thin slices gives it a characteristic lustre, whilst 

 incipient decay renders it dull and opaque. Any local departure 

 from the natural colour peculiar to the species is an indication of 

 incipient decay. The deterioration that sets in directly growing 

 timber passes maturity generally shows itself first by a white 

 colour at the centre of the butt end of the log. This is not a 

 serious defect ; but the yellowish-red tinge subsequently assumed 

 indicates a loss of toughness and tenacity, and suggests that the 

 log is not well fitted for constructive work. So too spots of 

 discoloration scattered through a log, especially at its butt end, 

 are liable to prove centres from which serious decay, caused or 

 accompanied by 'parasitic fungal moulds, may spread. This 

 remark does not apply, however, to the so-called pith-flecks or 

 medullary spots, which are often numerous in woods when perfectly 

 sound. The reddish-brown tinge known zsfoxiness is a clear sign 

 of advanced decay, unfitting wood for any purposes requiring 

 strength ; but Oak is very often much prized by cabinet makers 

 when in this condition, merely on account of its colour. 



Odours and resonance of woods. The odours of woods, 

 such as the resinous smells of Deal or Teak, the fragrance of Cedars, 

 Toon, or Sandal-woods, the characteristic perfume of Camphor- 

 trees and the unpleasant smells of the Stinkwood (Ocotea bulldta) 

 of South Africa and the Til (OreoddphnS fcetens) of Madeira, may 

 sometimes be of use in discrimination, as, to an educated ear, 

 may the notes given out by different woods when struck by a 

 hammer. In the manufacture of musical instruments the wood 

 must be of uniform structure, even -grained, free from knots, well 

 seasoned, and unbent, so that each fibre may vibrate freely. The 

 notes emitted will vary in pitch directly with the elasticity, and 

 indirectly with the weight of the wood. 



Silver Fir (Abies pectindta), imported as " Swiss Pine," is em- 



