Notes on the Properties of Wood. 115 
sandy soil, we find the Fir (Pzzus silvestris), beautifully 
red inside; in the same condition we find the Fir (Pzxus 
mughus), on turf soil, where there is an abundance of 
water ; but when we look at it on lias soil it shows broad 
yearly rings and hardly any colour at all. The Larch tree 
again in such soil develops itself well with a rich colour. 
The cause for these appearances must, therefore, rest with 
the chemical condition of the soil and its effect upon the 
individuality of the Fir. Oaks generally furnish good 
timber when grown slowly in dry ground, whilst those from 
wet soil appear considerably spongy. Similar results are 
obtained with other trees. 
Trees cut in summer give lighter wood than when felled 
in winter time. The cause for this may probably be 
ascribed to the fact that in winter a large amount of 
nourishment is stored in the stem, which, during the spring 
and summer, is spent for the formation of blooms and 
leaves. 
We call hardness of the wood the resistance which it 
opposes when another body enters it. If wood were an 
equal body, like minerals, we should be able to determine 
its resisting power or hardness; but it being differently 
built, and whilst trying its hardness other properties inter- 
fere, we cannot arrive at a decisive result. Sometimes a 
wood has very hard fibres but little body, that is, it is 
lighter built than another wood with soft fibres and a full 
body. It is, therefore, unadvisable to judge the hardness 
of a wood according to its fibres. Experiments to ascer- 
tain the hardness should be made across the stem, and not 
upon a longitudinal section, and, although there is no in- 
strument which leads us at once to a definite result, we can 
generally arrive with a saw at a fair conclusion. Many 
persons constantly employed on wood are of the opinion 
that it becomes harder if it is worked or barked off whilst 
green. 
Wood, as a porous body, contains, in its natural state, 
whether dead or alive, a certain amount of moisture. By 
the loss of that moisture, or with the increase of the same, 
the bulk of the wood either contracts or extends. If we 
have a piece of wood where this action takes place only 
upon one side it is obvious that the piece will alter its form 
or shape. The consequence of the loss of moisture is also 
the warping and the splitting of the wood. The inner 
structure of a stem is irregular; for instance, we find the 
inner moisture of a yearly ring to be more than on its 
