The Cordova daily times., 1921-04-18
LIMNORIA IS
 JUST OPPOSITE
 FROM I'EREDOS
Their Method of Attack on Filing Begins on Outside and Within Year Great Pile Is Nearly Eaten Through

SAN FRANCISCO, April 1S.-The , ship Cyprus Wakefield once tied up to a California wharf which looked i perfectly sound and trustworthy, ! During the night rather strong off shore breeze sprang up, and the next morning the ship was sighted out in the bay towing after a large part of the quay. When the shipping com panys officials investigated the cause of the phenomenon, they found that the supposedly solid wooden piles on which the wharf was built were bored out, and the piles had snapped off like pipestems when the ship tugged at her hawsers. At an other harbor a whole colony of houses built upon one of the wharves was dumped without warning into the water. Some time later seven freight cars which had been run out on a solid-looking pier quite as unexpected ly sank out of sight in the bay
 Such are the dangerous pranks played by that marine borer, the teredo The teredo is a worm with a hard auger for a head. He is, in very. fact, the worm that turns. He may bore any size of hole up to one inch in diameter. When he is young he bores a very small hole, thus gaining entrance into a pile un- noticed Once inside, he grows rapidly and can so completely honey comb the pile in a few months that it will not even support it's own weight. It is sometimes possible to | hear the sound of his bit when he is at work. but otherwise there is little outward sign of his presence
 Quite the opposite from the teredos in their method of attack are the marine borers called limnoria. Linn noria begin on the outside of the pill ing and in less than a year make it 1 look like half eaten stick of candy | When teredos and limoria get to work on the same pile it usually lasts about six months. Both of these marine borers infest the waters all along the Atlantic and Pacific coasts and are In reality serious national menace.
 The problem of guarding the struc- lures of our thousands of miles of water front against demolition by teredos and limnoria has stimulated great deal of American inventive genius. Hundreds of schemes have been tried, from the rigging up of floats which scrape the sides of the piles with the rising and falling of the tide, to the dynamiting of harbors to destroy all animal life in their depths. One scheme which aroused much hope involved the use of a pile built up of several blanks and there fore full of cracks. The supposition was that the teredo would not cross a crack, but, although the teredo may have had scruples in this mat ter, it soon became evident that the limnoria did not. The limnoria found the cracks a shelter instead of barrier.
 The forest products laboratory has recently proposed plan for the study of the marine-borer problem covering the entire coastal waters of the United States. It has just com pleted the first unit of this program. If you visit a movie theater show ing the international news weekly, you may see what the laboratory has been doing in cooperation with the American Wood Preservers' Associa- tion and district 5 of the forest serv- ice toward the protection of piling in San Francisco bay. It is said that marine borers came into this bay clinging to the ships of the gold-rush days. At least the borers have been very active there ever since. In the last two years alone they have caused damage amounting to fifteen million dollars.
 One of the facts brought out clearly in the recent piling survey is that of the diverse methods of protection that have been tried the most prom ising is that of treating the piles with creosote. Properly creosoted wood piles are very distasteful to both limnosia and teredos, and have re- mained unattached for periods of 25 years, while neighboring untreated piles lasted from six month to two unarS