Lysigenous structures


Softwoods (pitch pine, Douglas fir, larch, and if available Southern cypress and kauri), because of their chemical composition (low hemicell-ulose, high lignin, and high cellulose content) are intrinsically more chemically resistant than hardwoods, especially for alkaline conditions where they are also less likely to produce coloured extracts (cf. hardwoods with tannins). Softwoods are generally of straighter grain than hardwoods which is an advantage in vat construction as it confers maximum strength and minimises the risk of distortion and permeability which could be introduced by sloping grain. (The longitudinal to transverse permeability ratio averages 10 1 for various wood species.)  [c.962]


The chemistry of essential oils and artificial perfumes Volume 2 (1922) -- [ c.0 ]