CHAP. CV.

coryla'cea;. quf/rcus.

1787

more or less watery, according to the soil and locality in which it grows, andnaturally weighs more from a warm climate and dry soil, and when the treehas attained its maturity, than under contrary circumstances.

Tredgold observes that the wood of the Q. sessiliflora, which is of a darkercolour than that of the Q. pedunculata, is also heavier, harder, and moreelastic. To ascertain their relative value, he tried an experiment, and the fol-lowing table exhibits the results : —

Q. PEDUNCU- <2. SESSILI-

la'ta. flo'ra.

Specific gravity - '807 '879

Weight of a cubic foot in lbs. - - - - - - 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. - * 115<)2 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 weightbeing 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 fracturethan the Q. pedunculata. The strength, elasticity, toughness, and hardness ofthe 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 toAtkinson ( Hort. Trans., 2d ser., vol. i. p. 336.), splits clean, and is best adaptedfor split paling, laths, barrel staves, dowels for flooring, and similar uses; andas 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, itis 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 thisspecies from old buildings has generally been mistaken for that of the sweetchestnut. This discovery was simultaneously made by Fougeroux and Dau-benton about the year 1780. (See Mem. Scien. Mathe. dc ITnsiilut, &c., 1.Trim. 1807, p. 307.) Atkinson adds that the wood of Q. pedunculatais stiffer than that of Q. sessiliflora; and, though it maybe broken with aless weight, yet it requires a much greater weight to bend it than Q. sessilifloradoes; and it is, therefore, better calculated for beams, or to bear the greatestweight in a building without bending. The wood of Q. sessiliflora, accordingto 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, whichare framed of it, have lasted many centuries, without being in the slightestdegree deteriorated. It also makes better fuel than that of Q. pedunculata.Nichols appears to refer to Q. pedunculata, when he speaks of “ the trueEnglish 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, “ theworkmen in the forest call the durmast oak,” and which, from his reference toMiller’s Dictionary, and his observations in another work, appears to be theQ. sessiliflora, has the wood “ not so strong, hard, or durable, as that of theEnglish 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 kindsof oak, he adds, was not known in the year 1700, when some of the enclosuresin the forest were planted with acorns taken from the durmast oak. ( Obser-vations on Oak Trees, §c., in a Letter to the Earl of Chatham, p. 26.) Thisdurmast 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 theNavy, &c.) as having “ the acorns in clusters close to the twig, withoutany footstalks; and the leaves with short stalks, usually about half an inch inlength.” (p. 67.) The acorns of the true English oak, on the other hand, hesays, “ grow on fruit stalks, like cherries, from about 1 in. to 2 in. in length;