414 
The white American Oaks have in the South that is to say, in their optima station a specific 
weight of 89, and the Black Oaks of 75. In the North, the White Oaks have only a specific weight of 77 
and the Black of 70. 
These observations have a very great interest from the point of view of industrial utilisation of 
wood, resistance to pressure, and fracture being a function of the specific weight. 
All the other properties of the timbers are, moreover, more or less affected by transplanting the 
species outside its habitat. Who does not know that in Australia the Eucalypt furnishes railway 
sleepers lasting from thirty to forty years without preparation, and that this same wood only lasts from 
ten to twelve years in Algeria under similar conditions ? Who does not know that the Pinue sylvestris 
(Scots Pine) of the Yonne, France, is useless to such an extent that, cut up in rafters and laths, one could 
not fix slatea on it? Who does not know that our fir-tree, when it is from too low altitudes, furnishes a 
fibrous wood without elasticity and strength, and to such an extent that the Jurassic commerce, which 
sells its inferior woods in Algeria, is discredited in our colony? Finally, who does not know, taking 
another train of ideas, that the Maritime Pine of the Landes is no longer in the Sologne (centre of France 
district of Orleans. J.H.M.) and Corsica; that the Australian Acacias, the precious producers of gum 
and tannin in the country of their origin, have only given inferior products in Algeria? 
It is necessary then to guard oneself from foolish enthusiasms and impress one's mind with the 
idea that introduced species will never seriously compete with our own. The Weymouth Pine, which has 
the reputation of being the best American wood, is justly known to be the worst in Europe. What can we 
then expect from Pinus resinosa, P. Banksiana, P. rigida, P. ponderosa, whose wood is less valued than 
that of the Weymouth Pine in th^ir country of origin? Does one imagine himself to be able to improve 
^eventually in the course of time, and by good cultivation, the timbers of the bad introduced species? 
Finally, the best thing for us to do is to continue to cultivate the oak, the ash, and the elm in the 
plains, the beech in the stony slopes, the fir and the spruce fir in the mountains, following as far as 
possible the indications of nature. In this way only we will obtain the best and the most useful products 
of the soil. So that if, nevertheless, for certain reasons, one is forced to employ certain species outside 
their natural habitats, it will always be necessary to be careful in the utilisation of their wood. 
The following notes from my pen in the Journ. Roy, Soc., Tasmania, 1914, p. 23, 
have some pertinence in this connection : 
Let us consider the question of timber for a moment. No two sticks of timber in a timber yard 
01 in the forests are precisely alike. The timber is subject to all the limitations of variation of the species 
from which it sprang. And if these nuances of variation are difficult to record in the species itself, they 
are difficult to interpret in the quantitative records of the timber tester. All that we can say is that these 
records vary between such limits as have been (perhaps arbitrarily) assigned to the species by the 
systematic botanist. To say that the quantitative results are variable between certain limits is another 
way of saying that the species is variable, that certain forms have been admitted under the banner of the 
species by the botanist. If the botanist changes his views as to the diiection and amount of variation 
in a species the timber-tester must modify his figures accordingly, or persuade the botanist to alter his 
views. There is nothing final about timber tests, and the only way to render them comparable is to 
render available with them the fullest particulars as to habitat, size of tree, year and season of felling, 
and subsequent treatment, relative position in the trunk of the tree of the test piece, particulars in regard 
to the meteorological conditions of the locality of the tree for as long a period as possible. Of each piece 
of timber a number of thin sections should be submitted to microscopic examination in addition, in order 
that clues may be obtained for the interpretation of the quantitative tests aforesaid. 
Quantitative tests are only valuable to the extent to which they are supplemented by specific 
particulars which will render the materials comparable. In old-settled countries a considerable amount 
of information has been accumulated which enables an expert to say the directions along which variation 
has proceeded. Scots Pine, for example, is not a definite entity like refined gold, but a living, plastic, 
variable something, and the results of the timber-tester must be variable, because he does not deal with 
a constant. Although we have aggregations of individuals which we label a species, it is pertinent to 
remind engineers that no two blades of grass in the field, no two leaves of a tree, no two trees, are 
absolutely identical. 
