CHAP. CV. CORYLA‘CEZ. QUE’RCUS. 1787 
more or less watery, according to the soil and locality in which it grows, and 
naturally weighs more from a warmi climate and dry soil, and when the tree 
has attained its maturity, than under contrary circumstances. 
Tredgold observes that the wood of the Q. sessiliflora, which is of a darker 
colour than that of the Q. pedunculata, is also heavier, harder, and more 
elastic. To ascertain their relative value, he tried an experiment, and the fol- 
lowing table exhibits the results : — 
Q. PEDUNCU- Q. SESSILI- 
LATA, FLORA. 
Specific gravity - - - - - - - - “807 879 
eight of a cubic foot in Ibs. - - - - - - 50°47 54°97 
Comparative stiffness, or weight that bent the piece 7-20ths of an inch 167 149 
Comparative strength, or weight that broke the piece - 322 350 
Cohesive force of a square inch in lbs. - < - - 11592 12600 
Weight of modulus of elasticity in lbs, for a square inch - = 1648958 1471256 
Comparative toughness’ - - - - - - - 81 108 
“ Each piece was lin. square, and sustained by supports 2ft. apart,the weight 
being applied to the middle of the length. Both specimens broke short off with- 
out splitting : the Q. sessiliflora bent considerably more at the time of fracture 
than the Q. pedunculata. The strength, elasticity, toughness, and hardness of 
the sessile-fruited’oak would render it,” he continues, “ superior for ship-build- 
ing, were it not so inferior in durability between wind and water, to the Q. pe- 
dunculata, or stalk-fruited kind.” The wood of Q. pedunculata, according to 
Atkinson (Hort. Trans., 2d ser., vol. i. p. 336.), splits clean, and is best adapted 
for split paling, laths, barrel staves, dowels for flooring, and similar uses ; and 
as it contains a greater quantity of the silver grain, or medullary rays, which, 
when the wood is planed, the workmen call the flower in the wood, it 
is more ornamental as furniture. The wood of Q. sessiliflora, on the con- 
trary, contains so small a portion of the silver grain, or flower, that wood of this 
paid from old buildings has generally been mistaken for that of the sweet 
chestnut. This discovery was simultaneously made by Fougeroux and Dau- 
benton about the year 1780. (See Mém. Scien. Mathe. de l'Institut, &c., 1. 
Trém. 1807, p. 307.) Atkinson adds that the wood of Q. pedunculata 
is stiffer than that of Q. sessiliflora; and, though it may be broken with a 
less weight, yet it requires a much greater weight to bend it than Q. sessiliflora 
does; and it is, therefore, better calculated for beams, or to bear the greatest 
weight in a building without bending. The wood of Q. sessiliflora, according 
to Bose and other French authors, though good for nothing for ship-building, 
because it soon rots under water, is of such great duration when kept dry, 
that the roofs of many of the old churches and cathedrals of France, which 
are framed of it, have lasted many centuries, without being in the slightest 
degree deteriorated. It also makes better fuel than that of Q. pedunculata. 
Nichols appears to refer to @.pedunculata, when he speaks of “the true 
English oak, such as are standing about Rinefield Lodge,” in the New Forest; 
“ finer trees, or better timber for ship-building, than which, I believe,” he adds, 
“are not to be found in the kingdom.” Another oak, which, he says, “the 
workmen in the forest call the durmast oak,” and which, from his reference to 
Miller’s Dictionary, and his observations in another work, appears to be the 
Q. sessiliflora, has the wood “ not so strong, hard, or durable, as that of the 
English oak,” which, he continues, “ is well known all over the world as prefer- 
able for ship-building.” The difference between the quality of these tWo kinds 
of oak, he adds, was not known in the year 1700, when some of the enclosures 
in the forest were planted with acorns taken from the durmast oak. (Obdser- 
vations on Oak Trees, §c., in a Letter to the Earl of Chatham, p.26.) This 
durmast oak, he describes (in a Letter on a new Way of planting Acorns, 
&c., included in his Methods for decreasing the Consumption of Timber in the 
Navy, &c.) as having “ the acorns in clusters close to the twig, without 
any footstalks; and the leaves with short stalks, usually about half an inch in 
length.” (p. 67.) The acorns of the true English oak, on the other hand, he 
says, “grow on fruit stalks, like cherries, from about 1 in. to 2in, in length ; 
