Hazel-wood with Reference to Conductivity of Water. 561 
Curve B. In this curve is shown the total area occupied by the 
cavities of the water-conducting elements in the complete transverse section 
of the wood at different levels. The areas are measured in sq. mm., but 
each unit in the scale for curve B is twenty times as long as the unit in the 
scale for curve A. As one would expect, this curve, giving a measure 
of the total conductivity as far as can be obtained in transverse section, 
Fig. 5. 
shows a gradual decline from base to apex. Compared with curve A, 
curve B does not fall so steeply at first; this accords with the presence of 
a greater proportion of mechanical tissue at the base, as suggested above. 
This is the case especially in H7. 
Curve C represents the percentage of the total area of the wood which 
is occupied by the cavities of the water-conducting elements. The figures 
obtained range between 3-21 and 20-26 per cent. The curve may be taken 
to indicate, as far as possible in transverse section, the specific conductivity 
