DOES CHARGING TIMBER PROMOTE DURABILITY.

Ashburton Guardian, Volume VII, Issue 1674, 28 September 1887, Page 2

DOES CHARGING TIMBER PROMOTE DURABILITY.

» . . • The general belief has long been that it does, and m accordance with this con* viotion the praotio has been widely followed Bat a contrary view of the Bubj^ot ia taken by Wood and Iron. That journal aay a Id a recent Issue — "As charcoal would endure for agea m plaoes where timber would decay speedily the praotice of charring the aurfaoe of fence posts and other timber has been repeatedly recommended m books and ephemeral publications, as eminently : worthy of adopt on. The theory upon which suoh a recommendation is based would seem to warrant a confident expectation of satisfactory results la practice, but repeated experiments with charred timber hare fnruiihed conclusive assurance that process will not promote its durability. Indeed.numeroua experiments have shown that charring promotes premature decay. Two posts split from the same log may be set side by aide m the ground, the earfaoe of one being charred and the other not, »nd it will be Been that ihe charred post will perish before the other. The same is true of railway ties and all snoh timber aa may be exposed to the altering influences of wet and heat. Could the entire timber be ohapged from its perish* able condition to one solid price of eharsoal, the durability wonld be promoted to a surprising length of time, ' but the strength of the material would be destroyed. When fence posts or other sticks of timber .are exposed to the rapid action of wet and heat, the surface will decay first. One might suppose, therefore, that when timber la enveloped by a layer of charcoal, the durability of the entire piece would be greatly promoted ; and aoch would be the case were It not for the fact that the charcoal ia not imper* vious to water ; and as water reaches the timber below the charred surface, decay will commence coon after the grain of the wood has been exposed ti the influences of the weather. When the change has once begun beneath the charred surface, the durable covering of coal will be of no service whatever m preoervlng any portion of the wood. Taking this ptaotloal view of the subject it will be perceived that if on y halt an inoh of the outside of « post be cham d, the post will not endure ii long as if the same thickness of wood had been left unoharred to waste away by slower deoay."