The Princeton union. [volume] (Princeton, Minn.) 1876-1976, 1893-12-07

with foul bottom she only made SIX
knots, though burning from twelve to
fourteen tons daily. 1t was also stated
that the government had expended
thousands of dollars in the testing OF
protective and anti-fouling paints and
compounds with results which give out
little encourag ement to further expert
ments. 1t is well known that the only
way of overcoming this difficulty is to
cover the ship with a sheeting of cop
per. Here, again, an obstacle arises.
The attaching of loose sheets of copper
to a steel hull inevitably leads to in
furious galvanic action, and by way Of
remedying this tendency war ships are
built with a wooden sheathing four
inches thick to insulate the copper
from the hull. The whole trouble can
now be removed by depositing a coat
OF copper In an yunbroken sheet over
the whole bottom Of the vessel. This
is done by applying to the
hull of the ship a portable galyanic
bath. 1t is found that single deposit
of suitable thickness over the hull Of a
vessel 400 feet long and drawing 20
fet of water can be made in less than
three days, and the whole bottom of
the ship can, at this rate, be plated in
eight or nine days. The process would
consume about $500 pounds of cop
per, which, at II cents per pound,
would cost 5000. A most interesting
problem in electroplating has thus at
last been solved and company has
been formed to introduce this method
of plating the hulls Of ships with cop
per-
Safeguards for Working Electri.
clans.
The announcement that means has
been~invented Of rendering any wire
charged with electricity instantly dead
opens up the question recently dis
cussed in an Engli,h electrical journal
of the better protection against acct
dents from heavy currents of work.
men in electric light and power sta
tons. 1t suggested. among other Inn
provements, that the insulation resist
ance of the rubber gloves and boots
worn by men engaged at high pressure
works should be periodically tested
Rubber gloves and boots are subject
to wear and tear, and however good
the insulation may be when new. it rap
idly deteriorates. tits stated that gutta
peIcha nodded boots, with no irons in
them, are more reliable than rubber
boots, as they retain their insulating
properties much longer. 1t is suggested
that all high-pressure bars, switches
and fuses shall be boxed in, so that the
opening of the box would cut Off the
current and render 1t impossible for it
to be turned OF while the box was open.
Again, m?nufact lrers are compelled to
securely fence in all belts, wheels and
other machinery, and high-pressure ter
m4nals, bars or switches should be
placed under similar restrictions What
is wanted is simple signal to indicate
to the most ignorant workman when
a bar or terminal or switch is charged,
and so warn him off. Such device
would excellently we'll supplement the
use Of the newly invented electric "cut-
OFF, in increasing the safety OF work.
men in electric light stations.
A Clever Feat In Chimney Building.
A clever feat in chimney building has
been accomplished at Nancy, France.
1t was found at spinning works that,
owing to an increase of the power of
; the plant, the existing chimney did
not give sufficient draft for the number
Of boilers, and one: Of two things had
to be done-either 10 build new chin
ney alongside the old one or to in
crease the height Of the latter. While
the queStiCr was being deHberlted a
local builder offered to add 80 feet to
the existing chimney, making height
Of 100 feet in all, without interfering
with the work CT the mills. His offer
was accepted, and, aided by another
nervy mar, he fixed a series Of light
steel ladders to the chimney by means
Of iron hooks driven in between the
courses Of the bricks, erected pulley
at the top Of the chimney, and flight
Of scaffolding all around, and then, hay
ing lowered the ccrnice surrounding
the chimney, they built on the top at
the rate Of about feet to feet per
day. The whole work occupied eight
days. and Was perfectly successful