The Colorado statesman., 1922-09-23

is being done at the request of Charles
H. Burke, United States commissioner
of Indian affairs, and will cover one
year.
Mr.. Burke, having in view the i'm
provement of health conditions among
the Indians and demonstration of or
ganized service among the various
tribes to prove whether 1t Is possible
to instruct Indian mothers particularly
in health methods, urgently requested
that the Red Cross assign trained per
sonnel to the task.
~ am very solicitous to get into
the Indian service some young women
trained for welfare work" said MIR.
Burke. 81 know what the American
Red Cross has done in encouraging
the counties in the various states to
employ county nurses. l am sure IL
we have some cooperative assistance
it will show that 1t Is possible great
ly to improve health conditions on the
reservations"
Great Value of Geophone.
AS the result of experiments made
by the bureau of mines, the geophone,
novel instrument used amid the
reek and slaughter of the World
war for the detection of earth
and rock sounds made in the con-
structon of military mines and tun-
nels, promises to become an active
factor in the saving of the lives OF
miners entombed as the result of fires
and explosions. In the course of tests
In 40 hnrnuniG
mental coal mine near Pittsburgh,
blows with n sledge on the coal face
were heard, by means of the geophone,
ut a distance of $50 feet, with various
rooms and entries intervening.
On suspended pipe line, light
hammering with the knuckles was de-
| tected at distance of 1,500 feet. Or
dinary talking and singing could be
detected through $50 feet of solid
coal. BY the use of two geophones,
one instrument to each ear, it is pos
sible to determine the direction from
which a sound is coming through the
earth, and thus to locate the approx
mate position of an entombed miner.
| The bureau gives recommendations
for n signal code of poundings by
sledges or other means which will es-
| tablish communication between the
rescuing party and those entombed.
Another promising use of the geo
| phone is in the location of leaks in
! water pipes. BY means of the instru-
ment is is possible to hear water cir
culating in the pipes of ordinary city
mains situated 10 to Is feet below the
surface. Tests conducted at busy
corner in the downtown district of
Pittsburgh located a leak in n water
main which the water company had
for two weeks vainly sought to de-
tect.
It's a Small Sesmograph.
The mine geophone is sensitive, yet
extremely simple and easily portable.
The instrument was invented by the
| French during the war to detect sap
ping and underground mining opera
tions. 1t was developed by the United
States engineers, and the instruments
now used by the bureau of mines were
made according to plans drawn by
them, except for the Introduction of
different diaphragms. The geophone is
essentially a small seismograph, as 1t
embodies the same principles as the
ponderous apparatus that records
earthquake tremors. 1t really consists
of a lead weight suspended between
two electric diaphragms cutting across
small air-tight box. If the instru-
ment is placed on the ground and any
one is pounding or digging in the VI
| cinity, energy is transmitted as wave
motion to the earth, and the earth
waves shake the geophone case. The
geophone, therefore, transforms the
earth wave into an air wave, which is
heard by the ear as sound, and at the
same time magnifes the wave so that
the sound is louder than If the ears
were placed in direct contact with the
! earth.
The observations of the bureau of
mines indicate that the geophone
should be quite useful in the location
of mine fires. Usually a mine fire
makes enough noise, either by draw
ing air or by breaking off slate and
coal. to be heard for I, considerable
distance through the coal and even
| through the strata above The dis
tance that these sounds can be heard
depends great deal on the nature
of the strata above the mine. .'et the
sounds originating at a mine fire
should be detected through 100 to 300
feet of cover and through 500 to 800
feet of coal.
Geophones supply quick and fairly
accurate method of mine surveying.
| If two tunnels were being brought to-
gether from any direction, the prog
ress of the tunnels could be observed
by means of the geophones, and their
relative positions determined.
Another application of the possibill-