The Democrat. (Scotland Neck, Halifax Co., N.C.) 1884-1896, 1894-02-22

Shipmasters Entering the Narrows
Now Tell the Exact State Of
the Tide.
New York Herdld.)

The United States Coast and GeOdetlc
Survey established come months ago
tidal indicator on the edge OF the
wharf at Fort Hamilton, which, when
once understood, is likely to be OF much
value to vessels of all kinds passing in
and out of the harbor.
Az far as is known it is the first OF
Its kind ever constructed and Tor that
reason it WAS thought we'll to allow it
to run for some months before making
public announcement of its existence,
In order that it's continued operation
might be assured. A small model of
1t was exhibited at the Worlds Fair by
the Coast Survey, attracting much sur
vey attention from those interested IN
tidal matters.
The coast survey self-registering tide
gauge was during many years at Sandy
Hook. Many objections to the con-
tinued use OF this location presented
themselves during the last few years,
and about two years ago it was deter
mined to remove it to its present To-
cation at Fort Hamilton, and last spring
plans for the construction of the large
indicator referred to were prepared.
Any one passing through the Mar
rows may notice at the foot OF the
wharf at Fort Hamilton, small wood
en- building, inside of which the self
registering gauge is kept and over
which the tidal indicator is displayed.
The latter appears rs large semi-circle
with Its diameter resting ON the roof
of the tide house. The outer circular
edge of the scmi-circle is divided into
spaces by means of heavy black lines
which can readily be seen from the
deck of passing vessel at any point
In the Narrows.
WHAT IT SHOWS.
These divisions are numbered by
figures in black, so large that they can
easily be read by the aid of an ordinary
marine glass from the greatest distance
possible for passing vessels, These
figures indicate the height of the tide
In feet and the shorter division lines
show half feet. A pointer turning
about the center of the circle sweeps
along the inner edge of the graduations
as the hand of a clock moves over the
dial, only that in this case it moves to-
ward the left when it is falling. At
any moment the pointer indicates the
depth of the water above or below the
plane of reference used in constructing
the charts issued by the Survey, which
Is that of mean low water. Atextrene
low water the surface of the sea is
lower than this plane, and the indie
ator shows this by pointing on the
left OF the zero line-toward the
minus sign shown near the left edge of
the semi-circle.
The rise and fall of the tide is so
slow that it is impossible, OF course, to
know whether it is rising or falling by
simply looking at the pointer, but by
An ingenious arrangement an arrow
head placed In the centre of the disk
is made to point up as long as the tide
is rising and down when falling. Thus
by looking at the Indicator the naviga-
tor can tell the exact stage of the tide
and whether it is ebb or flood.
now 1T WORKS.
The index pointer is moved by means
OF cord or wire passing over = large
wheel to the axis of which the pointer
Is fixed. One end of the cord Is fast
ened to float which moves up and
down with the rise and fall of the
tide. To the other end a counterpo;se
1s fastened, so that, as will be easily
understood, the wheel moves in one
direction while the tide is falling and
in the other when it is rising.
To prevent the disturbance of the
float by waves due to wind or passing
vessels, 1t is confined in long box to
which the water is admitted through a
few small openings In this way
while any general change in the level
OF the sea affects the float, short waves
and momentary disturbances do not.
One great advantage of such an in