FOR GREA T BRITAIN AND IRELAND. 89 



ments show greenheart to be more durable than any other 

 wood, remaining sound for 19 years, teak for 13, also 

 beefwood. 



The various timbers of the pine and -fir tribes of trees 

 show the commencement of the mischief by the Limnoria 

 terebrans, some at 13, others at 1 8 months, after exposure. 

 The salter the water, the more vigorous are the worms in 

 their attacks. Fresh water coming down an estuary from a 

 river may check, but does not prevent their ravages. The 

 writer has even seen greenheart destroyed, and it is merely 

 a question of time. Greenheart being comparatively 

 durable, as regards other kinds of .timber, would always be 

 used but for its great cost. 



PROTECTION OF TIMBER. 



Mr. Stevenson suggests that Memel logs for inside piles 

 might be sheathed over with greenheart, as from their 

 position they would not be chafed by vessels. Copper 

 sheathing and scupper nailing has often been found for 

 a long time effective. The nails are driven in closely 

 together and rust into a compact surface, and the oxide 

 enters into the outer skin, which for a time defies the 

 worms. Any small aperture, however, will admit the 

 enemy. 



The process of creosoting was confidently believed to 

 be effective against the worm, but every engineer now 

 knows it is not so, and that they will attack timber treated 

 with creosite, even black in colour, and smelling strongly 

 of the solution. 



Mr. Thomas Stevenson particularly mentions that 

 Mr. D. Stevenson draws attention to the fact, that great 

 destruction happened to thoroughly creosoted timber at 



