246 
J. HOPKINSON-EATE OF GEOWTH OF 
John Hay first mentions these two kinds of oak in the second 
edition of his ‘Synopsis’ (1696), where he points out certain 
differences in the timber they produce, saying of Q. latifolia mas 
[ Q.sessiliflora - ] : “Lignum ipsum vim adstrictoriam validam obtinent; 
unde utilia sunt ad fluxum quemcunque sistendum.” Lightfoot, 
in his ‘Flora Scotica’ (1777), comparing the sessile with the 
pedunculated oak, says that “the tree itself is more humble, and 
the timber harder and higher colour’d;” and Sir J. E. Smith, in 
his ‘Flora Britannica’ (1804), remarks of Q. pedunculata: “Arbor 
formosa, ligno utilissimo, duro, tenaciand of Q. sessiliflora : 
“A priore differt ligno minoris pretii, . . Cooper, in the 
‘ Botany of Sussex’ (1834), where he says that “ the Navy contracts 
specify that Sussex oak shall be used,” controverted the then 
general opinion that pedunculata produced the best timber, and 
pointed out that the two trees could be identified by their wood, 
however much worked up, that of Q. pedunculata showing in 
transverse section “a vast multitude of medullary rays” not seen 
in that of Q. sessiliflora , which is so like chestnut that when taken 
from our old buildings, in which it has been much used and found 
extremely durable, it has very generally been mistaken for it. 
It may be added that from the colour of the wood, pedunculata is 
known to foresters as “ white oak,” and sessiliflora as “ red oak”— 
a distinction not kept up in the timber trade. 
Perhaps the most valuable summary we possess of this much- 
debated question is in Loudon’s ‘Arboretum’ (1838), under the 
heading “Properties and Uses” of the Oak, where the following 
statement is made : “In comparing the wood of Q. pedunculata 
and Q. sessiliflora , the former is found the most easy to split, and 
the stiffest and the easiest to break, and yet the most difficult 
to bend; while the latter has the advantage over the other in 
toughness and weight.” A comparative view of the weights and 
of the heating powers of the woods when used as fuel is then 
given from Hartig, as quoted in the ‘ Dictionnaire des Eaux et 
Forets.’ (I only give the weights arrived at.) 
Q. p. Q. s. 
lb. oz. lb. oz. 
The wood, when green, weighs ... 76 13 ... 80 5 
,, ,, half-dry, weighs ... 65 9 ... 67 12 
,, ,, perfectly dry, weighs... 52 13 ... 51 10 
The results of experiments made by Tredgold are also given as 
follows:— 
Specific gravity 
Weight of a cubic foot in lbs. 
Comparative stiffness, or weight that bent the piece 
7-20ths of an inch ... 
Comparative strength, or weight that broke the piece ... 
Cohesive force of a square inch in lbs. ... 
Weight of modulus of elasticity in lbs. for a square inch 
Comparative toughness 
Q. p. Q. s. 
0-807 0-879 
50-47 54-97 
167 149 
322 350 
11,592 12,600 
1,648,958 1,471,256 
81 108 
