1892-93-] The SJtipworm. 73 



in the East Indies, and vessels built of it have been known to 

 last from thirty to fifty years. In weight it is much lighter 

 than greenheart. The specimens exhibited were cut to the 

 same dimensions, and weigh respectively 3 lb. 8 J oz. and 2 lb. 

 8 \ oz. Two years ago, when fresh cut, they weighed 4 lb. 

 13| oz. and 3 lb. 6 J oz. Like every other kind of timber, 

 teak is liable to premature decay if not properly and gradually 

 seasoned. Indian teak (Tcctona grandis) is the produce of a 

 tree of the order Verbenaceaj. African teak, or rather African 

 oak, belongs to the Spurge family. Its timber is too heavy 

 for general use, but it is adapted for steam- vessels, as it stands 

 a great degree of heat. The teak grown on high, dry, and 

 open land is generally of a fine quality, close, compact, and 

 abounding in a mild oil, which exerts no injurious effect upon 

 the iron bolts driven into it. That grown in the dense forests 

 of the wet, low-lying alluvials, on the contrary, is lighter, 

 coarser grained, and contains an acrid oil, which not only 

 affects iron very materially, but even to a certain extent 

 poisons and inflames the hand pierced by its splinters. As 

 every one knows, the Indian teak forests are now under 

 Government protection. 



Many remedies have been tried, and expedients resorted to, 

 in order to baffle the Teredo, but the majority of these have 

 resulted in failure. Curious poisoning compounds, coal-tar, 

 and even the antiseptic or preserving power of creasote, 

 though the timber be still black and emitting its pungent 

 odour, are unable totally to prevent it. The only absolute 

 method of prevention is to replace timber structures with 

 stone or iron ; but the element of increased cost at once 

 steps in, even if the material be readily obtainable. Copper 

 and yellow-metal sheathing for wooden ships has long ago 

 become a sine qita non. Even with copper sheathing, where 

 only partially carried out, Teredos have caused extensive 

 damage above the water-line. Copper-sheathing and scupper- 

 nailing are often successfully employed as protection for piles. 

 The scupper or broad-headed nails are driven so closely as 

 almost to touch each other, corrosion takes place, and the 

 oxide of iron, entering into the outer skin of the wood, renders 

 it hard enough to resist the animal. Green twigs of pine or 

 other wood placed among piling have been tried with some 



