Ash-wood with Reference to Water -conductivity . 263 
of the buds at the apex of this shoot to develop. It was observed that this 
part of the shoot was alive at the resumption of cambial activity in the 
spring, for the section showed some development of new elements, though 
very slight as compared with that in the lower internodes. The highest 
value recorded for curve C was 9-5 per cent, at internode 11 in A 6 , while 
the maximum for A8 h at internode 4 reached 6*9 per cent. The lowest 
value was i*68 per cent, at internode 2 in A3. The percentage of ‘ conduct- 
ing area ’, curve C, is lower at the base of A 3 than at the base of A 4, while 
the total ‘ conducting area ’, curve B, is about the same ; this is because the 
larger area of wood in A3, internode 2, contains a higher proportion of fibres. 
Comparison with the re suits obtained for Hazel. There is a general 
resemblance between Ash and Hazel in the figures obtained for their stool 
shoots. The forms of the curves are similar, showing on the whole a decline 
in absolute conductivity with a rise in specific conductivity from the base 
of the shoot towards its apex, the latter falling again near the end. 
The actual values for specific conductivity, curve C, however, are much 
lower for Ash than for Hazel, taken as a whole, the limits of variation for 
the shoots examined being as follows : 
Plant. Ash. ' Hazel. 
Range of values for curve C i*68 to 9-5 per cent. 3*21 to 20*26 per cent. 
This is in agreement with the results obtained by Professor Farmer, 1 
for the two kinds of wood in question, by his experimental method of 
determining specific conductivity. His figures are quoted below : 
Stool Shoots of Ash. Hazel. 
Normal range of specific conductivity 14+10 31+9 
Thus in both cases the figures obtained for Hazel-wood are about 
double those obtained for Ash-wood. In order to account anatomically for 
this difference we may compare the diameters of the water-conducting 
elements and their distribution, as shown in the present investigation. For 
the shoots examined the ranges of variation for the average and the actual 
diameters are as follows : 
Stool Shoots of Ash. Hazel . 
Range of values for curve E in p 27-85 to 10*14 23*27 to 4-9 
Rang~ of actual diameters in /x 80 to 3 48 to 2 
It is evident that, on the whole, the water-conducting elements are 
wider in Ash than in Hazel, so that the reason for the lower specific con- 
ductivity in Ash does not find its explanation in this feature. Turning to 
the distribution of these elements, the ranges of variation for the shoots 
examined are as follows : 
Stool Shoots of Ash. Hazel. 
Range of values for curve D 32 to 633 115 to 4,000 
1 Farmer, J. B. : On the Quantitative Differences in the Water-conductivity of the Wood in 
Trees and Shrubs, Parts I and II. Proc. Roy. Soc., B., vol. xc, 1918. 
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