ZOOLOGY. 363 



with two or three coats of white lead, white zinc, red lead, tallow, or any good 

 strong-bodied paint, and the piles would be secure as long as the charring 

 and paints remain uninjured. Sheets of copper are used by all the mercantile 

 and naval world as the very best article. It lasts longer and is cheaper in 

 the end than any other metallic substance. Iron soon corrodes and becomes 

 loose, the barnacle and sea- weed fasten on it much more than on copper; 

 sheets of zinc have been used, but they soon wear away ; lead is too heavy. 



Any strong-bodied paint, such as white zinc, white or red lead, verdigris, 

 Ross's metallic, Edwards's red three coats of these paints will secure the 

 bottom of a ship one or two years from the salt-water worm. Three coats of 

 hot coal tar and three coats of hot naphtha, applied to dry wood that the 

 pores may be filled with the liquid, will keep the animal off, provided these 

 substances are not rubbed off so as to leave the wood naked. It is quite pos- 

 sible that, after a year or two, the paint would become insipid, and come off 

 in sheets or scales familiarly called "scaling off;" whenever this takes place, 

 the wood is in danger. The coal tar and the naphtha may, in a year or more, 

 pass off by being dissipated, drawn out by the flowing and ebbing tides. It 

 is certain, that as long as the above substances retain their purity, and can 

 be kept on the wood, the wood will be perfect from the water ; and I am sure 

 the worm cannot develope itself, unless the water reaches the wood. 



It has been suggested, that if wood were first saturated with corrosive 

 sublimate and then well painted, it would be an excellent preventive. It 

 would most certainly protect the wood from the ravages of the worm ; but it 

 would be found to be quite troublesome to saturate the bottom plank of a 

 large ship before or after it was put on the frame of the ship, lliree coats of 

 white zinc paint would have the same effect to keep the animal from the wood, 

 as the poison and two coats of white zinc paint. 



The bark of all trees, as long as it can be kept on, is positively one of the 

 best securities for piles, except copper : copper is superior to all metals or 

 substances known as regards protection from the ravages of the salt-water 

 worm. "White zinc paint is superior to copper in keeping the coral deposits 

 off of the bottoms of ships. The deposits in the "West Indies are in the form 

 of vegetation, viz. trees with then- branches, all tubular, and containing 

 insects. In ISTorfolk harbor, the common barnacle and often the oyster are 

 the deposits. These accretions are great hindrances to the sailing of ships : 

 when a ship's bottom is filled with sea-weed, or the common barnacle, or 

 any coral formation, the sailors say the ship is "very foul" and cannot sail 



fast. 



To preserve piles, I would drive all I could with the bark on. There is no 

 danger whilst the bark is kept on. The barnacle on piles does no injury. 

 Charring is excellent, provided the fissures are filled with hot coal tar, or some 

 other substance of equal virtue, such as the paints already named. White 

 zinc paint will be found excellent to keep the shell-fish from the wood where 

 piles may have the bark broken off before being driven. 



I believe that three coats of white zinc paint are next best to copper as a 

 preservative against the ravages of these destructive evil-doers. 



