Hevea and Castilloa, the resin is present in large proportion in the latex derived from young trees, and diminishes in amount as the tree ages.
The presence of more than a small percentage of resin in the latex leads to the production of rubber containing much resin, which seriously depreciates its commercial value for most purposes.
Of the suspended substances, grains of caoutchouc, drops of resin and oil, proteid crystals and starch grains may be mentioned.
A process devised by him for the manufacture of illuminating gas from turpentine and resin was in use in New York for a time.
In height; the wood, though soft and deficient in the resin that gives durability to the timber of some species, is valued by the southern carpenter and cabinetmaker for its lightness, its fineness of grain, and the ease with which it is worked.
The resin does not affect the unbroken skin, but may be absorbed from a raw surface, and will then cause purging.
The wood is soft and nearly white, but contains much resin, which when fire has run through the forest exudes, and, having in this half-burnt condition a sweetish taste, has given the common name to the tree; the wood seems to be formed slowly; from its smooth grain it is valued for indoor carpentry; the saccharine burnt resin is used as a laxative in California.
This may be Aquilaria agallochum, a native of East India and China, which supplies the so-called eagle-wood or aloes-wood, which contains much resin and oil.
Examples of resin acids are abietic (sylvic) acid, C19H2802, occurring in colophony, and pimaric acid, C20H3002, a constituent of gallipo resin.
Buried in this clay-marl are found large deposits of the fossil resin which becomes the kauri gum of commerce; and on the surface extensive forests are still a great though diminishing source of wealth.