The daily morning journal and courier., 1901-11-30

ton of the grain of the wood, unless turned aside by some. obstacle, in Its l path, such as knot, spike or another ! burrow.
 | It lines its tube-like passage with a
 thin culcareous deposit, which serve as protection to its crystalline body. No matter how many teredoS may be operating in the same piece of timber, no excavation will be found breaking
 in to another. How the artisans, work ing within the interior of the timber, can so unerringly avoid obstacles in their path is puzzle to scientists. The
 section of log measuring but IS inches in diameter, yet contained over 800
 teredo holes by actual count.
 To obtain live teredo means a dili-
 gent and in many cases a disgreeable
 search. The writer made a number of
 visits to various wharves, but 1t was
 not until an extremely low tide that
 success attended his quest. Great care
 must be exercised ill dislodging the
 creature if it is to be kept intact, while
 photographing the soft, watery mass
 will prove no easy task
 Many persons enormously charge the
 teredo with the damage done by
 limnoriae, minute insects that swarm
 upon the surface of immersed timbers
 and eat in toward the heart. Every
 piece of piling is beset with enemies within and without, and it is always
 question which will cause the ultimate destruction of the timber.
 The teredos bore into the lower end of the pile in such numbers that at length it breaks off and floats away; the limnoria makes its attacks at about half-tide mark, and if given sufficient time will eat the timber completely in two. Where the bottom is foul and muddy, the teredo completes its work first; but on a firm, sandy bottom the limnoriae win the day. The teredo does not work with the same rapidity in all waters, They are worse in Alaska than in southern California, and at various points upon Puget sound but a few miles distant from each other they work with varying degree of voraciousness, much depending upon the character of the bottom. A wharf left to itself soon becomes tottering ruin. They are carefully watched, and as quickly as piles are destroyed they are replaced by . pile driver which drives new tiinbers into the bottom with an immense hammer operated by steam power.
 Loggers are careful to construct their booms in places where streams mingle | with the salt water in order that their | logs may not be injured before reaching | the saw-mill. The Robertson 1og-raft | recently removed its plant | from Puget sound to the Columbia river in order to escape the teredo, which rendered one-third of its timbers worthless before raft of sufficient size could be got together for towing.
 How to protect tiinbers from their in sidious foes has been under considera- ton for years. Tn 1868 Dr. Avenarfus, 3 German chemist of note, made a from creosote which was fairly effective, but 1t did not meet with general favor on account of It's tnfiam- evaporation and destructive ness to wood fiber.
 It Is well understood that there are materials which will keep the teredo from destroying wood, pro- yided they can be made to stay on the wood; but the solving action of salt water is so great that 1t will destroy 7 he great percentage of them. In the southern California a considerable of eucalyptus bling is used. This wood withstands the action of the eredo for from three to seven years, ,ut the growth Is limited in quantity md size, and is not of sufficient inn ,ortance to cut any figure commerci- illy.
 The government demands the use of ,est-proof timber in all its wharves md harbor works. and railroads and ther private enterprises are following he example. The writer recently made careful examination of dock built f prepared timber which had been uilt for several years, and could not md the trace of q teredo. In the fem er-piles, however, which were un- rotected, teredos and limnoriae were olding high carnival-T. G. McCurdy l Scientific American. ,
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