38 TKCHNKAL I'i:( tl'KKTIES uF WuOD. 



and for most coDifers does not appear to counterbalance the 

 advantage of the softness of the moist fibres. Hence, Scotch 

 pine, larch and spruce woods are more easily sawn green 

 than dry ; but in the case of certain soft-fibred loosely textured 

 woods, the pliability of the fibres counterbalances the advantage 

 of moisture, as for instance in black poplar, aspen, birch, 

 willow. Sec, the timber of which is generally easier to saw dry 

 than green. 



If we take the resistance to the saw across the fibres oHered 

 by beech wood as 1, Gayer's own experiments in the case of 

 freshly felled wood give the following results : — 



Resistance 

 to saw. 



Silver-fir, spruce and Scotch pine . . . =0'50 — 0*60 



Maple, larch, alder =0'75— 0*90 



Oak =1-03 



Sallow, aspen and birch .... =1'30 — 1"40 



Lime, willow and poplar . .... =1-80 



(c) Resistance to Pressure and Friction. — In many cases con- 

 sideration arises as to the resistance wood ofters to pressure 

 and friction, and against thrusts and blows ; it needs no dis- 

 cussion to show that heavy woods resist these actions better 

 than light woods. 



The knife hardly deserves mention as a forest tool, but, when 

 used with the hand, its action unites that of the axe and saw 

 more than that of any other tool ; it aflbrds, therefore, a 

 suitable test for approximately classifying the degrees of hardness 

 of woods. 



Nordlingor, from average results obtained with difterent tools, 

 gives the following classification of woods according to their 

 hardness : — 



Hard as bone : Barberry, box, privet, lilac. 



Very hard: Common dogwood {Cornus samiuiiua, L.), yellow 

 dogwood (C. Mas, L.), whitethorn, blackthorn. 



Hard: Robinia, field-maple, sycamore, hornbeam, wild cherry, 

 service-tree, buckthorn, elder, yew, pedunculate oak, mahogany. 



Fairly hard: Ash, holly, mulberry, mountain-pine, plane, 

 quince, Turkey-oak, elm, beech, sessileouk, [sweet-chestnut, Tr.]. 



