Ellsworth American. [volume] (Ellsworth, Me.) 1855-current, 1912-02-14
THE GYRo COMPASS.
Improvement on the Magnetic Needle
In Use for $50 Years.

K
| its usefulness, at least for steam vessels.
The bureau of navigation of the navy
! has decided that it must go. In its place
there is being installed in the warsbips,
| that gyroscope compass which 1t is SAID Il
so far superior TO the magnetic compass
that they are not in the same class.
So long as ships were built OF wood. the
magnetic compass was as good guide as
| the mariner needed, though its sbortcom-
ings were such that to understand its use
! required much study To begin with, the
magnetic compass, except on single meri-,
/ dian of longitude. does not point 10 the
/ north pole, for the very obvious reason that
| the magnetic north pole is many hundreds
| of miles to the south of The effect OF this
| is seen in the fact that in Iceland the COM
pass needle points almost due west, and in
| mort bern Alaska due east. Because OF
this, allowance must be made for varia-
ton before one may know where lies the
true north, and before he may discover
what allowance to make, latitude and
| longitude must be known.
| With the advent of steel ships came
| complications in the use of the compass
on which no one had ever reckoned. The
vast amount OF metal close to and sur
rounding the compass sometimes made
| that instrument useless. This source OF
deviation finally WAS controlled by the
use OF iron balls, one or more, placed in
| proximity to the compass, but even this
/ failed to be permanent remedy, and the
compasses OF big ships must be examined
! frequently ana adjusted. The great need
/ for absolute accuracy is seen when it is
realized that an error of one half of one
degree in the compass means that the
| ship may be thirty miles off her course at
the end of a voyage across the Atlantic.
| In modern wsrships the compass deyia-
ton Is even more than it is on merchant
| ships. The presence of great amounts OF
me,al, some OF 1t close TO the compass,
/ makes the adjustment a matter OF grave
concern to the navigator. 1t is probable
that many OF the accidents that have
taken place in the manoeuvring OF war
ships have been caused by an iil-adjusted
| compass.
1t is a festure of the gyroscope, which |
was discovered by Foucault in 1852, that |
rapidly spinning body free to move in all |
directions has the power of finding the |
axis Of the earth by assuming position |
with its axis parallel with the earth's.
On this basis scientists here and in Ger |
many began working on independent |
lines, but toward the same end, and both |
produced a compass entirely free from |
magnetic influences.
| priaHv uy.oaktng tho 4,,.ry.ao
compass is gyroscope, with a roter about |
eighteen inches in the diameter, propelled |
| by electric power, 5000 to 5000 revolu- |
| tions a minute, and suspended in a frame |
work by piano wire. When it Is set going |
| 1t Immediately begins to seek the me-
| ridian. To the top of the swinging roter |
is attached the compass card. The roter |
revolves in a vacuum.
| Early last spring the American gsro
compass was tried for five days on the Old |
Dominion liner Princess Anne, between |
/ New York and Newport News, and as re- |
sult of the success there attained it was |
| tested again on the United States torpedo |
boat destroyer Drsyton. In the Drayton |
the gyro compass was placed in maya |
zine, way down in the hull over the keel |
where it was surrounded by metal. A |
magnetic compass would have been use |
less in such place, yet the gyro, when |
started 80 degrees OF the meridian found |
the north in forty-two minutes.
The tests we're made in rough weather |
and at all rates of speed, the Drayton be-
ing one OF the fastest boats in the United |
States navy, yet it stood up perfectly. |
The navigation board has decided that the |
\ magnetic compass has found its superior, |
and they are being installed on all the big |
ships.
Following the Drayton tests a gyro
compass vas installed in the battleship |
Delaware before she started on her trip to |
Europe to participate in the coronation |
ceremonies. One of the great faults OF the |
magnetic compass on warships is that the |
jarring when big guns are fired often
throws them out as much as five degrees. |
and 1t was feared that this jarring might |
seriously affect thu gyro. During the sa- |
luting, however, whole broadsides were
fired by the Delaware with her biggest
guns, and the new compass did not budpe. (
An examination of the gyro compass !
SHOWS that, its most wonderful feature,
n~xt to the way it finds the north, is the
tenaeity with which it holds it. mag i
netic compass is held to its position by a |
force so slight that breath will disturb /
1t. SO weak in this force that when the
compass is artifieially DETECTED up to give I
five degrees it often has not the power to l
return, unless started on its way. The
power that holds the gyro to the meri-
dian, on the other hand, is more than
"ooo times as great, and it is beyond the
combined strength of two men to drag if
the least fraction of degree out OF it's
course. when the gyro is moving 5000
| revolutions minute.
comparison Of the American with the
GERMAN gyro compass shows many points
In favor of the former. A property of the
gyro is that when IL ia 20 rriaa -. . -