CHAP. CV. CORYL/SCEIE. QUE'RCUS. 1787 



more or less watery, according to the soil and locality in which it grows, and 

 naturally weighs more from a warm climate and dry soil, and when the tree 

 has attained its maturity, than under contrary circumstances. 



Tredgold observes that the wood of the Q. scssiliflora, 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 : 



Specific gravity ....... 



Weight of a cubic foot In Ibs. ..... 



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 Ibs. . 



Weight of modulus of elasticity in Ibs. for a square inch 



Comparative toughness ...... 



<l. PKDUNCU- d. HKSSILI- 



LA*TA. FLO*RA. 



8(17 -H79 



50-47 54-97 



167 149 



322 350 



11592 12600 

 147 1256 



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 

 species 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 Mem. Scien. Mathe. de VInstitut, &c., 1. 

 Trem. 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 Bosc 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 Q. 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. (Obser- 

 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 2 in. in length ; 



