218 DESTROYERS OF SUBMERGED WOOD — MURPHY. 



for their absence in such localities as we have named, by reason 

 of the muddy or unclean water leaving a deposit of silt, in their 

 cells or burrows, and in this way sealing them up so as to destroy 

 the tenant or make the cell uninhabitable. It is further notice- 

 able that any piece of timber partially covered by mud, slime or 

 algae is exempt from these attacks, although timber in the same 

 place not so covered is being destroyed by them. 



From these observations one might infer that some external 

 application such as cement, lime bitumen or coal-tar, if repeated 

 as required, would arrest their ravages if not end them. 

 These conjectures, of course, require confirmation, though they 

 seem not improbable. I may mention, however, that a solution 

 of lime will not kill the Lminoria, immediately. I have had 

 them in a glass containing a strong solution of lime for two days 

 and some of them then seemed active. 



One method which is used to avert their destruction is to 

 cover the piles or submerged wood-work with copper or zinc 

 sheeting ; but this covering is so expensive .that it is not gener- 

 ally employed. It is an important practical problem to deter- 

 mine some cheap, ready and effective method or some means 

 whereby we can approach nearest to a cheap and practical 

 method of preventing the ravages of this little pest. 



In Nova Scotia we suffer more from the ravages of the Lim- 

 noria than we do from the Teredo, not because the crustacean is 

 more destructive than the mollusc, but because the habitat or 

 resrion of the Limnoria covers the littoral waters where most of 

 our wooden structures are to be found. Wooden wharves 

 or wooden bridges along the Baj^ of Fundy and from there along 

 the Atlantic coast as far as Whitehaven, suffer from the Limnoria 

 while the location of the Teredo is further east and north. The 

 zone of the Teredo's operations begins about Musquodoboit 

 Harbour. From there to Whitehaven the work of both borers 

 may be traced ; and in some intermediate places both may be 

 observed at work on the same stick. There is no neutral ground 

 between them. Their domains overlap for a few miles, each of 

 the little borers becoming less abundant as we advance farther 



