126 HOMES WITHOUT HANDS. 



The ravages committed by this creature are almost incredible. 

 Wood of every description is devoured by the Ship-worm, whose 

 tunnels are frequently placed so closely together that the parti- 

 tion between them is not thicker than the paper on which this 

 account is printed. As the Teredo bores, it lines the tunnel with 

 a thin shell of calcareous matter, thus presenting a remarkable 

 resemblance to the habits of the white ant. When the Teredos 

 have taken entire possession of a piece of timber, they destroy it 

 so completely that, if the shelly lining were removed from the 

 wood, and each weighed separately, the mineral substance would 

 equal the vegetable in weight. 



The Ship-worm has been the cause of numerous wrecks, for it 

 silently and unsuspectedly reduces the plankings and timbers to 

 such a state of fragility that, when struck by the side of a vessel, 

 or even by an ordinary boat, large fragments will be broken off. 

 I have now before me two specimens of " worm-eaten" timber, 

 one of which is so honey-combed by this destructive mollusk, 

 that a rough grasp of the hand would easily crush it. Yet this 

 fragment formed part of a pier on which might have depended a 

 hundred lives, and which was so stealthily sapped by the subma- 

 rine miners, that its unsound state was only discovered by an ac- 

 cident. 



The copper sheathing, with which the bottoms of ships are cov- 

 ered, is placed upon them for the express purpose of baffling the 

 Ship-worm, and, though so expensive a process, is cheaper than 

 permitting the destructive creature to work its own will on the 

 vessel. It is possible, however, that an equally effectual, and very 

 much cheaper method of protecting ships and submerged timber 

 may soon be brought into active operation. M. de Quatrefages 

 has discovered that mercurial salts of any kind are instantaneous- 

 ly fatal to the Ship-worm, and that, by their use, not only the ex- 

 isting animals may be killed, but their eggs destroyed also. A 

 vessel that has been attacked by these pests may be rid of them 

 by throwing a few pounds of corrosive sublimate into the dock 

 where she lies, and it would not be very difficult to keep a special 

 dock for the purpose. 



The most effectual method, however, of checking the ravages 

 of the Ship-worm is, by saturating the timber with corrosive sub- 

 limate ; a process which is effected by exposing the timber for a 

 long period of time, so as to allow the sap to escape, and then by 

 forcing a solution of the metallic poison into the minute inter- 



