The morning news. [volume] (Savannah, Ga.) 1887-1900, 1895-12-22
DEMORALIzED WATCHES.
Electric Cars Responsible for Their
Erratic Movements.


From the western Electrician.
In one of the motor cars which runs into
the city a gentleman apologized, while
asking the time of his next neighbor the
other day, by telling how his watch, which
had never done him an i'll turn in many
years, had suddenly become unreliable.
The owner Of the lying timepiece- was
thoroughly ignorant of the cause, and
quite astonished when it was shown that
in all probability it was magnetism from
the motor which had demoralized the
| timekeeper.
The general public does not understand
I that magnetism, unlike electricity, cannot
/ be insulated. 1t may be absorbed, but the
/ absorbing material must be para-magnet-
I &c, that Is, a metal or something which
| can be magnetized. The most susceptible
material of that nature is iron, either
/ IN the pure state or carbOnized, or steel.
But how" he asked, does magnetism
/ get into the watch, and what does il
/ do when it gets there?"
To make the matter plain, something
/ like this was said I'm the first place,
| know that certain metals have no Atm
/ ity for magnetism, cannot be affected by
/ a magnet, as lead, tin, copper. etc while
/ others, notably iron and its compounds,
are not only capable of being attracted
/ by II, but Will retain a certain amount,
| or in other words, become magnets and
remain magnets until that magnetism is
removed.
There is great deal more Of this perma-
nent magnetism scattered over the earth
| than is generally known. If you take a
| needle from package IN store If the
| package has been lying in a north and
south position you viii see II is a magnet
/ If you float it carefully on the surface OF
a glass of water. 1t will turn round and
| point north and south, like compass nee
| die. In that case the magnetism comes
/ from the earth's polarity.
| II with a compass needle you test the
rail of street car mot an electric road
| you will find that rails lying east and west
/ are polarized crosswise, while those lying
/ Nearly every piece of permanently fixed
/ iron Will show polarity, that il is a mag
net, more or less powerful according to
| circumstances. The Rurer and softer il
| is, the more readily IL is affected, and the
/ sooner il loses the property Of magnetism
/ while the reverse is true with impure OF
| hard iron, steel being less readily affected
/ but retaining the magnetic property more
/ persistently.
Now, although gold and silver and brass
are all nOn-magnetfc, the watch is not
/ wholly composed of these metals. The
/ main spring of your watch is fine steel
| and several other portions OF the watch
/ are of the same metal. The magnetizing
/ of the main spring, the case spring. screws
/ ETC., Will generally do little or no harm
/ for these are comparatively stationary
/ But the little hair spring, which oscillates
/ back and forth many times a minute, is
| also steel, and being magnetized is irreg-
/ ularly acted upon by the magnetic force
4 OF the earth-the same force which tends
/ to hold the compass needle in a north and
1 south position.
| When your hair spring winds up. it is
/ pulled either one way or the other by
| the earths magnetism or by some other
magnet, according to the position of the
| watch, and when II unwinds It is pulled
| in the opposite direction and the con-
| slant worrying of the little, delicate
spring will thoroughly discourage it from
| doing perfect work This little spring
averages about five movements per sec
ond, or in round numbers, $4,000 per
day. so that very slight acceleratlon
| or retardation Of its motion at each beat
| would aggregate many minutes In q week
But there Is another affected portion
| in a watch, If magnetism gets into it,
| the balance wheel. This Is sometimes
| made up of metals which have different
co-efficients Of dilation and contraction
so that in an changes of heat and cold
| the size of the balance wheel, and con-
| sequently its rate of movement-five times
! per second-will remain constant This
| is sometimes made Of para-magnetic met
| al and may be affected by magnetism
| Now, as the iron safe in your office
| the iron joists under the floor, the iron
| front of the building, the columns and
| pretty much everything else iron in Inc
| vicinity of your desk is more or less
| magnetic, and as the opposite poles OF
magnets attract each other, and like poles
| repel each other, your watch may be in
| close proximity to a moderate magnet all
| day, and If II is magnetied, why the
| safe or the railing would have more effect
/
| erty.
The motor under the floor of the car
| creates what electricians call a magnetic
| field in every direction, and this influence,
while it is nothing that can be weighed
| tasted, felt or seen, saturates the air and
| everything surrounding 1t, with a de-
| creasing density as you recede from the
/ pole of the machine. At the pole 1t will
| hold several pounds of iron with a force
requiring a hard pull to release il when
| in actual contact. A hammer a heavy
wrench, a spike will be jerked out Of
your hand at a distance of an inch OF
| more.
Now, there is no insulator for magnet
| ism. The floor, the seat a cushion. cloth.
| ing-none of these are competent to stor
the effect, and distance only weakens the
| field Of saturation. A plate of iron may
| absorb the magnetism in part, but thas
| acts more in the capacity of a stralneH
! than a complete shield.
And that, sir. probably tells where your
| watch trouble Is.