THE BAY OF BISCAY. 227 



Thus large openings have suddenly been made in 

 ships at sea beneath the feet of the sailors, utterly 

 unsuspicious of the danger to which they were ex- 

 posed, and at the beginning of the last century one- 

 half of Holland was nearly engulfed in the waves, 

 in consequence of the piles which supported her large 

 dykes having all been destroyed and undermined by 

 the Teredos. 



Only one method has hitherto been proposed as a 

 prevention against the recurrence of similar disasters, 

 and this is by investing all submarine wooden struc- 

 tures with a complete metallic casing. The object 

 of coppering the bottom of ships is chiefly with the 

 view of protecting them against the attacks of the 

 Teredo.* Unfortunately, however, this method is 

 inapplicable for structures of submerged wood which 

 every year pay a very considerable tribute to these 

 destructive Molluscs. In our own day, however, 

 science places at the disposal of industry many 

 valuable resources which were unknown to our fore- 

 fathers, and I believe it will be found very easy to 

 destroy the Teredo within a given space, and con- 

 sequently to protect our wharfs and other wooden 

 structures from the attacks of these animals. 



The process which I am about to describe is con- 



* According to some experiments made in England, wood that 

 has been long macerated in a solution of corrosive sublimate is not 

 perforated by the Teredo. This mode of preserving wood is pro- 

 bably too expensive to be employed on a large scale. It seems to 

 us, however, that thin planks that had been thus prepared might 

 be employed for the bottoms of the small coasting vessels which 

 frequent the ports which are infested by these Molluscs, and this 

 method would probably be cheaper than the use of copper. 

 Q2 



