Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-06-08
EVERY DAY SCIENCE.
Methods for Protection Against the
Drill of the Sea Worm.
OLD PAPERS TO KEEP ICE WATER.
An Ocular Analysis Of the Antics Of Fall
ing Drop of Liquid.
WAR-sHiP THAT DESTROYS ITSELF
rrRErLRKp roH THE prspArcH. ]


The problem of protecting piling and
timber in submarine structures against the
ravages of the teredo and other marine in
sects has long been a vexed one. There are
"a species of the teredo, but the ship worm
is the best known. The teredo navalis has
long and flexible body terminating in cut
ting shells or bits, and is inclosed for the
sake of its protection in hose-like she'll,
which reaches from the exterior extremity
to within a short distance OF what is known
as the head. The teredo swims about for
awhile in search of timber, which it enters
by q very minute opening. The worm grows
at the rate of two inches month, and digs
a hole to accommodate its increasing size.
1t continues its progress for II or Is months,
propagates and dies. 1t reaches length of
10 inches, although one has been seen 1S%
inches in length. The teredo cannot exist
IN muddy waters, as piling from the Mis-
sissippi Sound has been examined after the
annual floods, when the river water is very
muddy, and the dead bodie Of the worm
have been found in these pies. Again, 1t
is proven that they can exist for short
time in fresh water, as at Brisbane, Austria
liza, they survive the annually recurring ex-
posure to fresh water from the floods, lasting
from two to three months.
The plans adopted for protecting piles
against these pests are numerous, the best
known and most efficient being to creosote
them, which is done by subjecJing the pile,
after being peeled, to steaming ten hours in
8 vacuum and u hours in q retort. IN which
the creosote is forced into the wood, taking
the place OF the sap. which has been with
drawn entirely from the wood. From 10 to
II pounds Of creosote TO the cubic loot OF
wood is about the right charge. The only
objection to this process is its first cost 1t
will not pay to creosote piles on this coast,
owing to the low price OF same compared
with creosote. A creosoted pile, say 4O feet
in length, is worth on the Pacific coast
about $50. Covering piles with copper has
been tried, and with great success, but as 1t
costs about the same as creosote, 1t Is obJec-
tionable on that account. Studding the ex-
posed parts of the pile with copper tacks has
been tried by the New York Harbor Com
missioners with success, but as this method
uses as much copper as the former and more
labor is necessary to put it on, the objection
is the same.
One of the plans divised consists in
slabbing the pile and tacking on tarred pa
per on the core, then covering the tarred
paper with the slabs we'll spiked on. A
recent inquiry made concerning the old
Dutch plan of closely driving long nails
into the timber below water line, has re-
suited in the rejection of that method.
Wrapping the piles with tarred canvas or
tarred paper and slabbing is generally
recognized as cheap and practicable. Sec
tions of piles thus treated, which have been
under water for seven or eight years at San
Francisco have been found to be almost en-
tirely proof against the teredo.