CHAPTER XTII. 



Destruction of Timber Marine Worms: Teredo navalisChelura tercbranaLim- 

 noria terebrans The Lepesma of the West Indies The Xycophago Rate at 

 which the Worm will destroy Timber Effect of the Worm on hard Woods Rot 

 in Timber Preserving Timber: Mechanical means Chemical means Corro- 

 sive Sublimate Sulphate of Copper Chloride of Zinc Creosote London Oils 

 Country Oils Scotch Oils Carbolic Acid Apparatus used in creosoting 

 Process of creosoting Aitkius' process Hay ford's process Charred Timber 

 Practice of Eastern Railway of Fiance Practice on New Zealand Railways. 



MARINE WORMS. The most destructive of these pests are the 

 Teredo navalis, or ship worm, the Chelura terebrans, and the 

 Limnoria terebrans. 



The Teredo Navalis is worm-shaped, growing generally to 

 4 or 6 inches long and J inch in diameter, but instances 

 are on record of its having been found far exceeding these 

 dimensions. The head of the worm is provided with a hard 

 calcareous substance or shell in two parts, working on a hinge, 

 and performs the office of an auger. The head, like the 

 gelatinous body, completely fills the cavity bored, and, as a 

 rule, the outward indication will bear no comparison with 

 the destruction going on within. The perforations of this 

 worm are generally in the direction of the grain, but frequently 

 across the grain, with many windings. The knots are always 

 avoided, sometimes by the most intricate twists, especially 

 when there are several worms close together. One worm will 

 never enter the boring of another, but will work round it, 

 leaving only a very thin partition between. The worm, having 

 once entered the timber, never works out of it, although it 

 will frequently approach to within one-hundredth of an inch of 

 the surface. 



It has been observed that the Teredo navalis, when possible, 

 enters .the timber at or near, but always above, the ground line, 

 and it does not appear to enter above the ordinarjr low-water 

 level; but inside the timber it has been traced up to about two 



