112 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
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 
efficacious 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 
