DENSITY OF THE RINGS OF TIMBER. 383 
is conjectured that Cesar did not mean the Scotch Fir (Pinus 
sylvestris), but the Silver Fir or Spruce Fir, Adies excelsa. ‘This 
conjecture is probably correct. We think, with all proper de- 
ference to Czesar’s evidence, that his sphere of observation was 
too limited, and his stay in Britain too short, to give him any 
claim to be quoted as an authority on the native productions of 
Britain. Czesar passed rapidly through a portion of the south- 
east of England, more intent, we may assume, on the motions of 
the enemy than on the vegetable produce of the country. But 
admitting that he noticed every tree in his line of march, it is 
not improbable that there might be other trees besides those 
which he observed even in Kent. The Beech might have 
‘abounded in Berks, Oxon, and Bucks, although comparatively 
scarce in the counties of Kent and Surrey. The learned Whit- 
aker tells us that the Beech was introduced by the Romans, 
and states as his grounds for this opinion that the British word 
for Beech, which he says is foighe, faghe, or faydh, is derived 
from fagus. The Cambro-British word for Beech, according to 
Davis (see Welsh Botanology, sub verbo Beech), is ffawydden. 
This may be from the same root as the Latin fagus. But it is 
rather slender proof that the Romans introduced the Beech into 
Britain. We know that the Beech is now a native of Britain. 
Where it gets possession of the ground it retains it. Its shade 
is so thick that scarcely any other seed will grow under it but 
its own, and in such places the seedling beeches are very 
abundant. 
When it first got a footing or a rooting on our chalk-hills, 
neither history nor etymology, nor even geology, appears to be 
in a condition to give us any satisfactory information. 
Density of the Rings of Timber. 
To the Editor of the ‘ Phytologist.’ 
Sir,—In your January number for the present year, “ Syl- 
vanus” inquires respecting timber grown on the north sides of 
hills and on the north sides of trees. It is pretty well under- 
stood that the sun’s influence affects the growth of trees and 
assists their development; and therefore trees grown on the 
northern declivities of most hills being of slower growth, the 
