554 THE POPULAR SCIENCE MONTHLY. 



when withdrawn, in October of the same year, the preparation was 

 found to be powerless as a protection against the teredo. 



5. Oil of Paraffine. The firm of Haages & Co., at Amsterdam, de- 

 livered to the commission some pieces of oak and red fir injected with a 

 substance produced by the dry distillation of peat, to which they gave the 

 name of oil of paraffine. In the month of July, 1860, the commission 

 placed at Stavoren and Nieuwe-Diep ten pieces thus prepared. They 

 were examined in the course of the same year, after they had passed one 

 summer in the water, and it was found that they had resisted the attacks 

 of the teredo. 



The commission conducted all its experiments thus : They placed in 

 the water ten pieces of each variety of wood, treated according to the 

 prescribed method, so that they could withdraw each year, during ten 

 consecutive years, one of the pieces to be submitted to examination. 

 In making the examination, they removed with an adze the outside of 

 the wood to a depth of some millimetres, which was sufficient to show 

 the galleries of the teredos, if there were any. The pieces found intact 

 were replaced in the water, and the following year their condition was 

 tested in the same way, by removing the shavings as before. By this 

 plan the commission felt certain that, if the blocks were not injured by 

 the teredo during several successive years, they did not owe that pro- 

 tection to a superficial covering, but that the wood itself resisted the 

 destructive efforts of the teredo, and that there would be no reason for 

 fearing that piles, prepared in a similar manner, would, at any time, 

 lose their power of resistance, when injured on their surface by water 

 or ice, or by slow dissolution of the active principle of the preserva- 

 tive substance. 



When the pieces of wood treated with oil of paraffine were taken 

 from the water in 1862, after a sojourn of more than two years, or 

 rather during three summers, traces of the teredo were found in the 

 pieces of oak, but not on those of red fir ; but when examined in No- 

 vember, 1863, fully-developed teredos were found everywhere, in the 

 fir as well as in the oak, in the pieces whose surfaces had been removed 

 by the adze, but not more than in those which had not been submitted 

 to any examination. 



6. Oil of Creosote. This is, as is very well known, a product of the 

 dry distillation of coal-tar, separated by distillation from the more vola- 

 tile parts, which serve for the preparation of benzole and naphtha, the 

 residuum being pitch. Experiments had already been tried abroad, as 

 well as in Holland, with this substance, and from the beginning of their 

 experiments the commission paid especial attention to this very impor- 

 tant method of preparation. 



Wood of various kinds, prepared with creosote-oil at the works of 

 the Society for the Preparation and Preservation of Wood, at Amster- 

 dam, was placed in the sea. in the month of May, 1859, at Flessingue, 

 Harlingen, and Stavoren. In the month of September following, at 



