55 6 THE POPULAR SCIENCE MONTHLY. 



the whole character of the opening, indicated clearly that it should 

 be attributed to some other animal than a teredo. 



As to the unprepared pieces, there only remained small ends, which 

 reached above the water. All the rest was converted into a spongy 

 mass, which broke at the slightest effort. 



The experiment with the creosoted oak was less satisfactory. In 

 all the pieces were found, here and there, galleries of the teredo, but 

 always in small numbers ; in sawing the wood, it was found that the 

 injuries were invariably in those parts where the color showed that the 

 oil had not been able to penetrate. Although, as far as is known, no 

 effort has been made elsewhere to preserve oak from the teredo, the 

 commission places great value upon experiments with this wood. In 

 fact, for many marine works, oak cannot be replaced by any soft wood 

 which absorbs creosote-oil easily. Hence, the commission has had 

 creosoted at Amsterdam, by a newly-perfected process, some pieces of 

 oak, which were exposed in 1864 at Nieuwe-Diep ; these will not be 

 examined until tested during three summers. 1 



Petroleum has also been recommended to the commission, but it 

 was not deemed worth while to experiment with it, especially on ac- 

 count of its high price; even although petroleum should prove to be as 

 efficacious as creosote-oil for protecting wood against the teredo, its 

 price would prevent its use for that purpose. 



Experiments with Exotic Woods, other than Ordinary "Woods 

 of Construction. The commission has not been able to make many 

 experiments in this direction. It acquired a certainty that the green- 

 hart of Surinam, the bulletrie, the American oaks, and wood as hard as 

 mamberklak, are not spared by the teredo. The commission received 

 a large piece of the wood of guaiacum, which had been five or six years 

 in the water at Curacoa, and was found to be entirely eaten by the tere- 

 do an evident proof that even the hardest woods are not safe from the 

 attacks of that mollusk. 



The commission has received, it is true, many communications 

 relative to different kinds of woods known to be poisonous to fish, but 

 it has not had an opportunity to experiment with them. We await 

 some light on this point, from researches which the Government has 

 ordered to be made at our possessions in both the East and West 

 Indies. 



Conclusions. By way of recapitulation, the results of the experi- 

 ments, tried by the commission during six consecutive years, were as 

 follows : 



1. The different coatings applied to the surface of wood, with the 

 design of covering it with an envelope on which the young teredo can- 

 not attach itself, offer onlv an insufficient protection ; these coverings 

 are likely to be injured either by mechanical means, such as the action 

 of the water, or by being dissolved by the water. Just so soon as 

 1 American oaks of coarse, open fibre are easily impregnated. Translator. 



