112 THE ECONOMIC MOLLUSCA OF ACADIA. 



Harbor, but does not account for their absence from the 

 remainder of the Bay where clear salt water is found. No 



■ doubt the low temperature of the water in the summer months, 

 making the conditions for their young so unfavorable, is to be 

 thanked for our comparative immunity from them. 



Such being the relation of Teredo to man's interests, it is 

 not surprising that great attention and much experiment 

 have been given by practical as well as scientific men to 

 methods of circumventing them. The most carefully con- 

 ducted and systematic experiments on record are those 

 described by Dr. Von Baumhauer in the first of the works 



■ mentioned below. It obviously does not come within the 

 scope, as it certainly is not allowed by the limits of a paper 

 of this character, to describe at length the experiments or the 

 •mode of application of the latter. Those practically inter- 

 ested are referred to the three papers below, that by Dr. Von 

 Baumhauer, the very excellent one by Mr. Murphy, and that 

 by J. W. Putnam, which, though it contains some errors of 

 natural history, appears to be sound and complete from a 

 practical standpoint. All of these are easily accessible. 



The Commission, of which Dr. Von Baumhauer was a 

 member, experimented with all means proposed to them by 

 inventors and others. Eight different methods of coating 

 wood were tried, including mineral paints, varnishes, poison- 

 ous substances, etc., but none of them proved of any value. 

 They tried six methods of impregnating wood with different 

 substances, including some of the very poisonous salts of 

 copper, iron and lead, only one of which proved efficient. 

 The successful one was oil of creosote — a coal-tar product. 



This method proved successful when good oil was used, 

 and to-day it is acknowledged by engineers that the only 

 eflBcacious way to preserve timber permanently from the 

 attacks of the Teredo is to thoroughly impregnate it with 

 creosote. The process must be thorough, for partially filled 

 timbers will be destroyed. The mechanics of the process of 

 impregnation are described in the paper by J. W. Putnam, 

 referred to below. It consists in forcing the oil under great 

 (Pressure into the previously prepared wood. Woods of loose 



