TEREDO NAVALIS IN NOVA SCOTIA — MURPHY. 369 



on wood previously roughened by a toothed instrument ; this 

 application was two millimetres thick. 



4. Method of M. Ripurjk, analogous to the preceding. 



5. Paraffine varnish, obtained by the dry distillation of peat, 

 from the factory of M. M. Haages & Co., at Amsterdam. 



6. Coal tar applied cold on the wood in several successive 

 layers, or applied hot on wood whose surface had been previously 

 carbonized. Some pieces were treated as follows : Holes were 

 first bored in them and filled with tar; then plugs were fitted 

 closely to the holes and driven in with sufficient force to make 

 the tar penetrate the wood ; other pieces still were painted over 

 with a mixture of tar with sulphuric acid, or sal ammoniac, or 

 turpentine, or linseed oiL 



7. Painting with colours mixed with turpentine and linseed 

 oil, amono; others, with chrome-o-reen or with verdigris. 



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8. Singing or superficial carbonization of the wood. 



The pieces of wood thus prepared were placed in the water at 

 the end of May, 1859, and the first examination, made toward 

 the end of September of the same year, showed that neither of 

 these methods afforded any protection from destruction by the 

 Teredo. There was one partial exception, and that was the piece 

 of wood treated according to No. 6 ; these showed only traces of 

 the Teredo here and there. But at a later examination, in the 

 autumn of 1860, when the wood had been exposed a year and a 

 half, these were also found to be equally severely attacked by 

 the Teredo. 



The i*esults of these experiments strongly convinced the Com- 

 mission that no exterior application of any nature whatever, or 

 modification of the surface merely, would give any efficacious 

 guarantee of protection against the teredo. Even supposing that 

 one or another of these means would prevent the young teredo 

 from attaching themselves to the wood, yet the constant friction 

 of the water or ice, or any accident, might break the surface of 

 the wood sufficient to give access to the teredo. 



This seems a proper place to mention a practice in general use 

 in Holland for warding off the teredo ; this consists in covering 

 wood with a coat of mail made of nails. This operation is very 



