The free press. (Poplarville, Miss.) 1890-19??, 1897-02-04
HOW MUCH is A KNOTT
veu Few Landsrnen Know It's value
EXPRESSED in Miles.

Expressed IN Miles.
In this day of record breaking by
ocean steamers, when every big steam
or that comes into port is expected 10
carry n record hung at yardarm, 80
10 speak, how many landsmen kho"
the meaning OF the term knot III
which rate Of speed at sea is chieny
expressed? 1t is purely and wholly
nautical term, having specific apphca-
ton to the speed and distance mace ny
a vessel moving in the water.
The word knot is the mariners
term for nautical mile, and It's use
is really derived from the log line useu
by navigators of the ocean when lhey
wish to determine the speed ana Tue
distance that the ship has propapiy
sailed in a given time. the log Ing
is an important and very necessary
part of a ships fittings; especially Is
this the case when, for several Gays 1t
sea. the navigator is unable, because
of the sun being hidden by clouds OF
thick weather, to get peep at II win
his sextant, from which the actual po-
stion of the ship is worked out. WIN
the data taken by frequent heaVlns
of the log "a small block or seetion
of wood with a long line attached anu
run out from the stern OF the 'essei
for a specific number OF seconus]' ho.-
ing the force and direction OF the Wino'
the possible currents, or other lhlu-
epces acting favorably or against the
progress of the ship, the navigator IL
enabled to calculate very nearly Al
overcast or foggy weather. aoou'
where his ship is at any hour OF the
day. This is called working out the
position of the ship by dead reckon
ing"
Every one who has studied the geo.
graphical table in his early school Gays
| will recall that part OF the slngsons
recitation running like this: SILKY
nine and one-sixth statute miles, Ut
sixty geographical miles, equal one ue.
gree of longitude at the equator.
Now. the difference between statute
mile and a nautical mile is that the
latter is about 500 feet greater than
the former. There are sixty geographl-
cal miles to each degree OF LATITUDE,
or to each degree Of longitude at the
equator, which divisions of miles are
called minutes" in the nautical Vo-
cabulary, hence the old saying,
mile a minute" AS there are 800 de-
grees, or meridians, of longitude, lhere
are 600 minutes, or miles, in the en-
tire circumference of the world, at lhe
equator; and it has been mathemau-'
cally determined that one minute-one
geographical mile-at the equatorial
circle is equal to 6,0S6.7 feet But II
has been the practice of mariners mol
to be too exact on small fractions when
measuring distance as great as mile
consequently the practice OF de1lnlns
a knot or nautical mile as equal &c
$3.50 feet, instead of 6,OS6.7 feet, mas
been generally adopted.
When the navigator desires to make
log-line by which to ascertain tht
speed which his vessel is making
through the water, he follows the con
slant 60S0 As the number of SECONDS
in an hour are to 6,0S0 feet, so are the
number of seconds in the time glass
Ito be used for measuring the snip
speed to the number OF feet in eacI
unit of measurement marked off on the
log line. If half minute go seconds
glass is to be used, the knots must DC
made so feet 8 inches from each other
and the number of these knots Whcl
pass from the reel over the stern while
the sand is running from the top bull
to the lower bulb of the glass is equa
to the number of knots or nautica
miles that the vessel would make II
an hour, providing the same condl
lions for speed continue.
For instance, if the engines of
steamship continue to make the sam'
speed during the hour, or if the force
of wind and spread of canvass of :
sailing vessel continue the same, thu
number of knots on the line passin.
from the reel while the sand is run
ming through the thirtysecond glass i
as good an actual measurement of tn
vessels speed through the water n
could be obtained, except that TIL
course should be measured by an &C
tual survey with instruments. II
was shown that the vessel was makin
ten knots, she would cover ten geo
graphical miles, or a little more thai
| III land miles mr. aIaypD and a hal
times $3.50 (5,2S0 feet being equivalen
to land mile). Hence, to speak o
the City of Paris having made 81
knots Or nautical miles in twenty-fou
hours, she covers a distance of 604i
land miles, as comprehended in rail
road distances, or a rate of % Ian
miles an hour, which is faster thai