On account of the time required to season timber in the natural way, various methods have been tried to effect the same purpose in a shorter time. One of the best of these is to immerse the timber in water as soon as it is cut down, and after it has remained about a fortnight in water, but not more, to take it out, and dry it in an airy situation.
Evelyn directs, to "lay your boards a fortnight in water (if running the better, as at a mill-pond head) and then setting them upright in the sun and wind, so as it may pass freely through them, turning them daily; and, thus treated, even newly-sawn boards will floor far better than those of a many years dry seasoning, as they call it:" * and he adds, "I the oftener insist on this water seasoning, not only as a remedy against the worm, but for its efficacy against warping and distortions of timber, whether used within or exposed to the air."
Duhamel, who made many experiments on this important subject, states, that timber for the joiner's use is best put in water for some time, and afterwards dried; as it renders the timber less liable to warp and crack in drying; but, he adds, " where strength is required it ought not to be put in water."† And he found, from numerous experiments, that timber which had remained some time in fresh water lost more of its weight in drying than that which was dried under cover; and he observed that green timber that had been steeped in water for some time was always covered with a gelatinous substance ‡
Timber that has been cut when the tree was full of sap, and particularly when that sap is of a saccharine nature, must be materially benefited by steeping in water; because it will undoubtedly remove the greater part of the fermentable matter. Duhamel has ascertained that the sap-wood of oak is materially improved by it, being much less subject to be worm-eaten; and also that the tender woods, such as alder and the like, are less subject to the worm when water-seasoned.* Beech is said to be much benefited by immersion; and green elm, according to Evelyn, if plunged four or five days in water (especially salt water) obtains an admirable seasoning.†
* ' Silva,' vol. ii., p. 217. † ' Transport des Bois,' p. 247.
‡ Ibid., pp. 164, 168, 171.
When timber is put in water it must be sunk so as to be completely under water, as nothing is more destructive than partial immersion. Salt water is considered best for ship-timber, ‡ but for timber to be employed in the construction of dwelling-houses fresh water is better.
M. De Lapparent recommends the following periods for immersion in water: - In river water one year; in fresh water frequently changed two years; in brackish water, which should be always changing, three years.
At the close of these several periods the boards intended for planking should be taken out and placed in store, or they might be left to season themselves naturally for two years before being worked up. As to rough timber for ribs, it should always be submitted to artificial seasoning previous to being used.