The morning news. [volume] (Savannah, Ga.) 1887-1900, 1894-07-15
CHARTS OF COASTS.
Three Thousand Carried by Each Of
Our Var Vessels.
Delicate Engraving Process-The Gen
erous Supply Furnished the Mer-
chant Marine-Where the Work Is
Dnna
From the Washington star.

not long ago illustrates the precariousness
of navigating huge ships of war near the
coast. This accident occurred while an
experienced pilot was guiding the vessel.
She was then on her trial trip. If she
had been in service, and entirely under
the control of the navy department, there
would have been no pilot aboard. The
officers of the navy are required to de-
pend on the charts which their vessels
carry for navigation not only along the
coast of the United States, but in all for
eign waters.
THOUSANDS OF CHARTS ABOARD SHIP.
Our ships of war carry about 1900 coast
charts apiece. With the aid of these they
are able TO enter any known harbor or
skirt any coast without the aid of local
pilot. Sometimes a INSTRUMENTATION
brings them TO grief, as in the case of the
unfortunate Kearsarge. But these &C
cidents are exceptional and are to be
charged to mistakes in reckoning
The carrying of so many charts is es-
sential because no one can know on what
short notice we may want to mass all of
our war vessels in one poFt-pOssibly on
the Asiatic, perhaps on the European
station. 1t would not be practicable for
all of these vessels or for many of them
in fact TO stop at some port of the United
States en- route for the purpose of getting
the appropriate charts. And it would not
be safe to trust to the tender mercies of a
local pilot, especially if we were on bad
terms with the nation whose coast we
were visiting.
Less than one-third of the 5000 charts
carried by our vessels are made by the
navy department. About 2, 100 of them
are bought abroad. OF course the chief
publications ofThe navy department are
the charts of our own coasts. These
charts are published not only for the use
OF the department, but for the benefit of
the merchant marine Charts are fur
nlshed to merchant vessels at the cost of
paper and printing. There is a regular
interchange of charts between the great
powers; and some of them make their
own ehgravlngs in reproduction of all the
foreign charts received. England does
this, and a, few years ago it was neces-
sary for the navy department TO 90 to
England for copies of charts made by our
own naval officers and published by our
coast survey. These were charts of
Alaska which were suddenly needed by
the navy department when the Bering sea
trouble began to look ugly. A hasty re-
QUESTION was made on the coast survey
for supply of the charts, and the reply
came that they had been photolitho-
graphed, that most of them were out of
issue and that they could not be supplied
The department then telegraphed to the
dispatch agent in London TO purchase
copies Of the charts there.
ENGRAVING CHARTS.
If the coast survey charts had been en-
graved on copper there would have been
no difficulty in obtaining prints on short
notice The British admiralty puts every
chart received on copper, and the number
of them owned by the British govern
ment must be something enormous OF
course a new chart is not made every
time change is discovered In the forma-
tion of a coast line or harbor Changes
are made very easily in the copper plates,
so that with a comparatively small ex-
pendlture they can be kept constantly
up to date" There are thirteen en-
gravers and three apprentices working
in the photographic office making cop
per plates of charts. In addition to
these engraVers, there is a force of
draughtsmen and force of printers. The
drawing of chart is necessarily q mat
ter requiring considerable skill and great
attention to mathematical exactness.
Each of the charts is drawn complete be-
fore it is engraved Then usually several
expert engravers are put to work on one
chart. Engravers, like artists, have their
speCialtieS. 1t is not every man, for ex-
aA4ApASy w AlO carts " Ill III lU,JUU QOJS with
steel point in the space of a square inch.
This work is done under microscope and
one man can do hardly more than square
inch of it in day,
MAKING THE TRANSFER.
The transfer of the chart from the
original drawing to the copper plate is
made In sections. The transfer agent is
sheet of very thin transparent fish clue.
This sheet is fastened over the drawing.
An engraver with a fine pointed steel
tool traces in the fish glue the lines and
points of the drawing underneath. The
MIN Is removed from the drawing. The
operator rubs graphite into the drawing
on the film. Then the film is laid in place
on the smooth copper plate with the
traced side down. OF course the adjust
ment of each piece of film to exact rela-
tlons with the adjacent parts of the draw
ing is very delicate matter. When the
him is in place a blunt instrument is
rubbed over the back of it, and when the
him is removed a graphite tracing of the
original drawing remains on the plate.
An engraver goes over this drawing, cut
ting it into the metal This transferring
is used for the drawing alone. Any let
terlng which may appear in the DESIGN is
drawn on the copper direct.
The printing of the charts from these
plates is very like the printing Of bank
notes. The plate is mixed with a roller
and then the surface ink is rubbed off.
hrst with sponges and afterward with the
bare hand. There is quite an art in the
correct manipulation of the plates. When
the rubbing is completed, moist piece of
paper is laid on the plate and it is put
through powerful hand press. The pa
per lifts the ink from the lines of the en-
craving and comes out with a clean copy
of the map. For the next COPY the plate
IS linked again and rubbed as before.
The charts, as they come from the
press, are taken to a drying room, where
they are subjected to heat for twenty
four hours. Then they are placed be.
tween sheets of leather under pressure
of $50 tons They come out of this press
perfectly smooth.
HOW CHANGES ARE MADE.
There are great many minor changes
IN coast charts which must be made by
hand. The coast survey has one clerk
who does nothing but put red streaks on
newly printed charts to indicate the light
thrown out by certain light houses. Light
house changes are not so frequent as the
changes in buoys. These the clerks in the
photographic Office are continually rub
Ding out or filling in on the printed
charts. Each chart, as IL is completed. is
stamped Aids TO Navigation, corrected
TO date, from information received TO
July l'-or whatever the date may be.
Where permanent change ia "A chart
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