The midland journal. (Rising Sun, Md.) 1885-1947, 1939-09-01
Traces Quakes;
Sounds Alarm
Novel Device Automatically
Flashes Lights on the
Control Board.

SAN DIEGO, CALIF.-Brighter
and brighter grew the red glow
from the bulb marked north; be-
low it on the switchboard a white
light marked "south" suddenly
came to life. The needle on the
nearby milliammeter juggled con-
NEUTRALITY-SUSPICIOUS., hundreds Of
miles away In the vast desert fast
ness Of Bajo, Calf, the earth was
quaking.
"That's north-south movement"
explained Fred w. Robinson, 49,
year-old amateur seismologist,
gazing intently at a switchboard of
Pickering bulbs and cavorting
gauges that recorded the temblors
of an apparently stable earth.
Robinson, an electrical engineer
who wanted to know "why" the
earth quaked, became interested in
seismology about five years ago and
has constructed from odds and ends
a seismograph that not only marks
on paper the movements of the
earth, but which rings chimes in his
nearby house, lights lights to show
the tendency of the shock and
moves a needle back and forth on
a dial, enabling him to see the
slightest shock that occurs.
Two Temblors in Japan.
Recent shocks recorded by Rob-
inson's seismograph have been of
varying intensity. Two have been
located in the northern tip Of the
Japanese peninsula, the other seven
Somewhere" near the upper end
of the Gulf of California in the I'M
inhabited sections of Sonora state in
Mexico.
Even as he spoke, the needle on
Robinson's milliammeter continued
it's nervous movements and by peer
ing through a magnifying glass it
was possible to view slight eccen-
trio motions Of the needle on the
paper. The earth beneath Robin
sons feet moved not the slightest.
The homemade seismograph re-
cords three types of quakes, those
which have north-south move
ment and those of a vertical move
ment.
Three ink-filled quilts leave a
track on the revolving drum. The
slightest earth shock writes its full
history on this drum and gives the
seismologist an insight into its char
acteristics.
From the scribbling recorded on
the seismograph drum, Robinson is
able to determine the quake's ap-
proximate distance, intensity and
type.
Despite the apparent completely
Of the seismograph machinery, its
operation is quite simple, Robinson
said.
Bars Transmit Disturbance.
Pieces of spring steel are imbed-
ded in a concrete block sunk deep
into the earth. Atop these three
foot steel bars are weights of $50
pounds giving them a construction
similar to an inverted pendulum.
When the earth quivers, these tenn
pered steel bars pick up the shock
and begin to vibrate. The vibra-
lions are then recorded on the paper
drums by means of attached arms
which magnify the intensity of the
vibrations so they may be inter-
preted easily.
Attached to a p1urnb-bob string is
a ring similar to those sought by
merry-go-round riders. Suspended
through the center of this ring is
brass rod. The slightest quake
causes the ring to sway and touch
the rod, closing a relay and setting
off a series of chimes in the Rob-
inson home.
The light bulbs are lighted by
electrical resistance set up by the
movement Of the axis when a shock
occurs. The waverings of the steel
springs are interpreted on a MILL
ammeter whose jigglings reflect the
earth's movements.