2 CRAIB—REGIONAL SPREAD OF MoIstuRE IN Woop oF TREES. 
had decided to limit the Ulmus experiments to elucidation of the 
one broad principle. It is unnecessary to supply the graphs for 
Ulmus as these are in general but repetition of those for Acer. 
It may be interesting to record one small experiment which 
although not carried out by a method ensuring absolute accuracy, - 
vet gave rather unexpected results which might be regarded as 
suggestive of future lines of investigation. 
In the case of one of the trees the annual rings were so broad 
that I decided to split the ring roughly into Spring and Summer 
wood and to examine these two separately. The result was that 
the Summer wood contained on an average about 10% more 
moisture than the Spring wood. This tree was then in the 
centre-storage condition. Unfortunately no equally broad rings 
were present in any of the other trees but some were just broad 
enough to allow of their being split and the result was that the 
Spring wood showed a decidedly higher moisture-percentage than 
the Summer wood. Apparently then when the moisture is stored 
in the centre of the trunk the Summer wood has the higher per- 
centage but when the moisture is moving outwards the Spring 
wood has the higher. In recording this small experiment I am 
well aware of the fact that the methods employed do not give 
results from which satisfactory conclusions can be drawn. No 
account has been taken, for example, of the difference in specific 
gravity between the earlier and the later formed wood of the 
year. In spite of this I think the results may be worthy of 
record.* 
II. Deciduous-Leaved Trees during the Leaf-bearing Period. 
From the condition of the last graph published} to the summer 
condition with, as I presumed, a large central comparatively dry - 
_area, the transition would seem easy. It was legitimate to 
imagine the large percentage of moisture just inside the cambium 
in March as very rich in sugar and as ready to be drafted to the 
cambium at its own level or higher up. The exhaustion of this 
store, rapid owing to the tree’s spring growth activities, would 
result in the summer condition as presumed. ‘The process is 
_ however no such simple one. j 
This paper is a continuation of that already publishedt and 
gives the results obtained from the following trees of Acer 
Pseudoplatanus :— 
1. Tree felled entire on the morning of 23rd April 1918. At 
this time the buds were just open and a few leaves here and there 
were showing. Growth had not yet begun on the trunk but the 
_* Notes on decidous Coniferae will be found 
oo: Soe Roy. Bot. Gard. Edin., vol. xi. ~ Sos: Pi. out. aus. 
tN — Bot. Gard, a vol. xi. No, LI. p. 1 (191 18). 
