96 
EXTRACT OF A LETTER TO THE EDITOR, 
had consulted all the best authorities on the subject, and therefore 
quoted him. 
But we do not consider botanists., whether practical or literary, so 
good judges of timber as a gentleman like Mr. Atkinson, whose busi¬ 
ness has so long and so directly led him to study the comparative 
character of the different kinds of timber used in buildings ; and 
from the particular attention which he has paid to ascertain which 
species or variety of British oak is really the most durable, we cannot 
for a moment doubt but that his conclusion is correct. 
The “ silver grain/’ alluded to by Mr. Atkinson and many former 
writers, are, we suppose, the concentric rings of cellular membrane 
which distinguish or divide the annual growths from each other; and 
are, we apprehend, what the workmen call “ the flower of the wood ” 
when exposed by the plane. These divisions are all nearly of equal 
thickness in the same butt of a tree which has grown freely ; but they 
differ very much on panels cut from the same butt. If a panel be 
cut directly through the pith, the graining, or flowering of the wood, 
will appear in nearly right or wavy lines from top to bottom ; but 
if cut from near the outside, or just within where the slabs were 
sawn off, then the cellular divisions, or silver grain, occupy full one 
half of the whole surface after it is planed; and merely because in the 
first case the saw passes through the divisions at right angles, whereas 
in the last case the saw cuts through obliquely, and consequently 
exposes more of the circumferential dimension. 
Mr. Atkinson remarks that the Q. pedunculata presents more 
of this silver grain than the Q. sessiliflora , in parts (we suppose) cut 
from the same parts of the butts respectively. This we cannot doubt; 
and the reason may be, that the former has thicker or more substantial 
cellular divisions than the latter, it being impossible there can be a 
greater number, especially as Mr. A. adds that the sessiliflora appears 
to grow as fast as the other. Another thing which may tend to increase 
the silver grain of the pedunculata , is, the well-known circumstance 
that the common oak makes two growths in the course of the summer, 
namely, the spring and midsummer shoots; and as the tree makes a 
pause before the midsummer shoots come forth, that pause will be 
marked by a thinner concentric line or division, when the timber 
is worked up. We have examined many oak trees for the purpose of 
guessing their age by counting the concentric layers, and, if we did not 
pay attention to these intermediate midsummer lines, we were very 
liable to over-date the age of the tree. 
We can corroborate what Mr. A, has advanced respecting the 
