26 i 
Ash-wood with Reference to Water-conductivity . 
Curve E gives the average diameter of the vessel cavities in the trans- 
verse section of the wood, measured in ju. The figure obtained for each 
section depends of course on the proportion of wide to narrow vessels, as 
well as on their actual widths. The curve keeps fairly level or may rise 
slightly from the base upwards for the greater part of the length of the 
shoot, and then falls again towards the apex. Only the fall is seen 
in the very small shoot A 8 e. Curve E reaches its highest point in 
Fig. 7. 
A 6 at internode 10 (the highest calculated figure being 27*85 \i at A 6 , 8), 
but this of course is only an average value. In all sections narrow as well 
as wide vessels are present, but on the whole they are narrower in the 
smaller sections, and the rapid decline of the curve towards the apex is due 
to the absence of the larger vessels. The highest diameters recorded in 
each shoot for a single vessel were as follows : 
Shoot No. A 6 A3 A 4 A 8 a A 8 h A8* 
Diameter of widest vessels in /x . 80 76 72 46 32 28 
