* In some of the large manufactories for cabinet-work, the premises are heated by steam-pipes, in which case they have frequently a close store in every workshop heated many degrees beyond the general temperature, for giving the final seasoning to the wood, for heating the cauls, and for warming the glue, which is then done by opening a small steam-pipe into the outer vessel of the glue-pot. The arrangement is extremely clean, safe from fire, and the degree of the heat is very much under control apparatus just described, but the veneering hammer alone. This is either made of iron with a very wide and thin pane, or more generally of a piece of wood from three to four inches square, with a round handle projecting from the one edge of the hammer head is sawn down for the insertion of a piece of sheet iron or steel, that projects about one quarter of an inch, the edge of which is made very straight, smooth, and round; and the opposite side of the square wooden head of the veneering hammer is rounded, to avoid its hurting the hand.
The table and both sides of the veneer taring been toothed, the surface of the table is warmed, and the outer face of the veneer and the surface of the table are wetted with very thin glue, or with a stiff size. The inner face of the veneer is next glued; it is held for a few moments before a blazing fire of shavings to render the glue very fluid, it is turned quickly down upon the table, and if large is rubbed down by the outstretched hands of several men; the principal part of the remainder of the glue is then forced out by the veneering hammer, the edge of which is placed in the center of the table, the workman leans with his whole weight upon the hammer, by means of one hand, and with the other he wriggles the tool by its handle, and draws it towards the edge of the table, continuing to bear heavily upon it all the time.
The pressure being applied upon so narrow an edge, and which is gradually traversed or scraped over the entire surface, squeezes out the glue before it, as in a wave, and forces it out at the edge; having proceeded along one line, the workman returns to the center, and wriggles the tool along another part close by the side of the former; and in fact as many men are generally engaged upon the surface of the table as the shop will supply, or that can cluster around it. The veneer is from time to time wetted with the hot size, which keeps up the warmth of the glue, and relieves the friction of the hammers, which might otherwise tear the face of the wood.
The wet and warmth also render the venceer more pliable, and prevent it from cracking and curling up at the edges, as should the glue become chilled the veneer would break from the sudden bending to which it might be subjected, by the pressure of the hammer just behind the wave of glue, which latter would be then too stiff to work out freely, owing to its gradual loss of fluidity; the operation must therefore be conducted with all possible expedition.
The concluding process is to tap the surface all over with the back of the hammer, and the dull hollow sound will immediately indicate where the contact is incomplete, and here the application of the hammer must be repeated; sometimes when the glue is too far set in these spots, the inner vessel of the glue-pot or heated irons, are laid on to restore the warmth. By some, the table is at the conclusion laid flat on the floor, veneer downwards and covered over with shavings, to prevent the too sudden access of air. Of course the difficulty of the process increases with the magnitude of the work; the mode is more laborious and less certain than that previously described, although it is constantly resorted to for the smaller pieces and strips of veneer, even where the foregoing means are at hand.*
* The former chapters were in type before the Author was aware of the existence of two excellent papers, by A. Aikin, Esq., F.G.S., etc, "On Timber," and "On Ornamental Woods," read before the Society of Arts in 1831 (see their Trans. Vol. L., Part ii. p. 140-170.) The Author is very happy to find, that so far as the present pages treat of parallel parts of this extensive subject, they are in general confirmed by Mr. Aikin, although the construction of the two papers is entirely different.
Mr. Aikin adverts in a very interesting manner to circumstances relative to the growth of the tree in its native forest, and the process of seasoning, etc, in which M. Duhamel's great work, Sur l'Exploitation des Bois, is referred to; and also to the luxurious employment of ornamental woods amongst the Romans as derived from the Natural History of Pliny the Elder. (Plin. Hist. Nat. xiii. 29 - xvi. 24-34.)
"By far the most costly wood was procured from a tree called citrus, a native of that part of Mauritania which is adjacent to Mount Atlas. In leaf, odour, and trunk, it resembles the female wild cypress. The valuable part is a tuber or warty excrescence, which, when found on the root and under ground, is more esteemed than when growing on the trunk or branches. When cut and polished it presents various figures, of which the most esteemed are curling veins, or concentric spots like eyes, the former being called tiger-wood, the latter panther-wood." - "Tables of this material appear to have been first brought into fashion by Cicero, who is said to have given for a single one a million of sesterces, i. e. 8072 l." - Others of these solid tables were sold at greater prices, and one as high as 11,300l.
"In the time of Pliny the art of veneering was a recent invention; and he descants in his usual antithetical way, on thus converting the cheaper into the most valuable woods, by plating them with these latter; and of the ingenuity of cutting a tree into thin slices, and thus selling it several times over. The woods employed for this purpose were the citrus, the terebinth, various kinds of maple, box, palm, holly, ilex, the root of elder and poplar. The middle part of a tree, he observes, shows the largest and most curling veins, while the rings and spots are chiefly found near the root. The veneers, or plates, were secured, as at present, by strong glue." - Pages 162-4.