The fact that resinous timber will withstand the action of heat and moisture, where other kinds will soon decay, seems already to Lave been known by the ancients, for Pliny says, tin) more odoriferous wood is, the more durable it is Indeed, the longer a tree has been used for pitch, the less enduring is the timber that, it yields; and it may be asserted, that the wood of thu C'onifera;, which is so useful for all kinds of carpenters' work, owes its usefulness greatly to the quantities of ri'Sin secreted in its titMues, they rendering it impermeable to water and making it thus capable to withstand its effects The resin becomes concrete after death by the evaporation of the essential oils which held it in solution Schacht, in his splendid work, "Dor Baum" (the tree), relates several instances of the wonderful durability of resinous timber This author examined tlio ruins of the castle Ehrenstein, near Remda, in Thuringii, one of the oldest extant in Germany, and found the wood (yellow pine), perfectly sound, and but little turned brown The old wood of the Canarian pine is also nearly imperishable on account, of the resin diffused in its tissue Schacht relates that the pillars of the dwellings on Teneriffa and rtran Canaria are still aa well preserved as if recently cut They were driven into the ground at the time of the Conquista, in 1402 William W Bates, of Chicago, 111, in a report on American ship timber, relates, also, numerous instances'of the great durability of resinous timber, among which the following may find a place here " The red and white pines of Oregon are largely used on the Pacific coast in the construction of the various parts of vessels They are considered so well fitted for tliis purpose that vessels have been constructed entirely of the denser sorts oi pine timber, both in Oregon and California MJlie yellow, or longleaved pine of Virginia and North Carolina is extensively used by Atlantic ship builders for planking, ceiling, stringers, beams, waterways, rails, keelsons, etc It is very durable, and when a lighter, yet solid wood is required, it is preferred to oak of whatever kind" The white or northern y;iue, according to Bates, is found at the head of the list of the softer woods used in building vessels of every description For the construction of liver steamboats, it is invalunble, and is sometimes used in ahnosT, every part of the boat, except, the frinno, above light water mark No wood is Eu! lobe better sid ptiH1 to withstand the san and weather, for with proper Si ariuning and reasonable protection, after the work is finished, it retains its properties as long as the best luivJ of oak Tho wood of the hackmatack or tamarack (the American latch), which io known for its density as well as for its gummy nature, is used for vessels in every part The sapwood should, of course, be excluded in this, as well as in all other instances, but the heartwood requires no seasoning before use, the shrinkage in weight being less than two pounds per cubic foot For lightness, strength, tenacity, and durability, it is unequaled The red, or Norway pine, when deprived of its sapwood, is found to be a firstclass material for top timbers, beams, deck planks, bulwarks, and ceiling; it affords excellent timber for masts, when large enough, and for all kinds of small spars The roots make very good knees and breast hooks Another proof of the unchangeability of resinous matter, is the amber, which, formerly, was considered as being of mineral origin, but is now decided upon to have lieen secreted, in a fluid state, from the Conifers of the upper tertiary and secondary strata From the ordinary resins it differs in yielding a peculiar acid, the succinic acid, upon being treated with alkaline lyes Goeppert succeeded in producing it artificially from Venetian turpentine, in digesting the same with twigs of the larch, for twelve months, in water of from 140 to 175 Fah