CRAIB—REGIONAL SPREAD OF MOISTURE IN Woop OF TREES. 3 
The small blocks were put in a drying oven which was kept 
at r100-105° C., and weighed at intervals of twenty-four hours 
until the loss per cent. in a twenty-four hours’ period was less 
than 0°5 per cent. The moisture content of the original block 
was taken as the loss of weight in drying, and this moisture 
content, expressed in terms of the dry weight, was calculated 
separately for each block. 
Graphic Representation of Results (Plates CLV—CLIX).— 
After calculating the moisture content of a number of specimens, 
I decided that probably the best method of illustrating the 
results throughout each tree was by graphs rather than by the 
tabulation of series of figures. The number of rings in each of 
the transverse cuts is plotted horizontally (2 mm.=1I1 annual 
ring), and the moisture percentage vertically (I mm.=4 per 
cent.). - In each case the line representing the middle line of the 
transverse cuts is taken as a base line representing a moisture 
content of 80 per cent., and these base lines are spaced out pro- 
portionately to the distances of the transverse cuts above ground 
level. The points plotted are the middle points of the small 
blocks as determined by the number of annual rings in each. 
No attempt whatever has been made to give the resulting 
polygons the appearance of graphs, as I thought it advisable in 
this preliminary investigation merely to join up the actual 
points plotted. 
In examining these graphs it should be noted that whereas 
the general trend of the graphs is comparable, any particular 
series of similar points may not be strictly comparable, e.g. the 
first observations in the cuts of the October tree (see Plate CLV) 
from below upwards represent the moisture percentage of the 
outer one, four, six, two, and seven years’ wood respectively. 
In the case of the October tree (see Plate CLV), the left-hand 
side represents the younger wood and the right-hand side the 
centre of the tree. In the remaining trees (see Plates CLVI- 
CLIX) the oldest wood is in the centre of the graphs and the 
youngest wood at the right- and left-hand sides, 7.2. in the 
October tree the graphs represent the moisture distribution 
from the outside to the centre, whereas in the remaining trees 
they represent the distribution from the outside to the centre 
in two directions. 
Coloured Illustrations (Plates CL-CLIV).—In addition to the 
graphs which, as stated, give the moisture distribution through- 
out the trunk of the tree, an attempt has been made to show 
diagrammatically the stages through which each part of the 
trunk passes in the leafless period. The circles represent the 
transverse section of the trunk, and the colour distribution 
corresponds to the moisture distribution. It must be noted here 
