The sun. [volume] (New York [N.Y.]) 1833-1916, 1914-07-12
PROBE EARTH'S CRUST
BY ELECTRIC WAVES
German Scientists Develop
Method for Exploring
Structure Of Globe.
FIRST TESTS IN 1880
Behring'S by Expedition in Africa
Result in Interesting
Discoveries.

A process for the exploration Of tho
structure Of the earth by means Of cleo
tr!cni raves and the employment OF a
neD iStreiess ,oupe apparatus Aas becn
developed by Or. Heinrich Loe1Dy and Or.
Gotther Letmboch OF Goettinoen, Dr.
Leimbdch has crttten OF his discover
for THE Sun. A translation Of his article,
ctfh the technical details omitted, toIiotos.
~ DR.. 0OTTHELF LEIMBACH.
Electricity was employed for the sx-
ploration OF me earth's crust as early as
1890 by r. w. Fox at cope: mines IN
Cornwall. A little later II was usei for
the same purpose by +. Reich and Theo-
dore Erhard Mt Freiburg. Saxony, and by
q. Barus In the development OF the
Comstock mines in Nevada. The principle
OF all these methods for the discovery Of
minerals depended upon tho action Of eler-
trio currents passing through tbs e1rth
upon the magnetic needle. the presence Of
the mineral being Indicated by the greater
or less deviation Of the needle when SUBJ
m'tted 20 the tests.
The difficulty. however. OF finding the
position of the current which had affected
the instrument made the results OF rom
paratively small value The same my be
said OF the more modern methods based
upon the same principle, which were In
troduced by the two Americans Daft and
Williams.
The end OF tho last century saw. through
the development of the .orincipls OF the
transmission OF electrical energy through
space without the use OF wires. the intro
duction and the first practical use OF wire
less telegrsphy. The success which Mar
conf achieved led 20 the great interest
In this branch Of science and also to 7
much wider understanding OF the trans.
mission OF energy through electrical
waves. The first efforts. however, to EN-.
ploy electrical waves in uncovering the
secrets OF the Interior OF the earth were
made by mining engineer, G. Truestedt
In 1901. He was followed almost i'm
mediately by a Hanoverian. II. Mueller. &c
whom a patent for a process was issued
Without any knowledge OF tho expert
rnents OF these two men. Or. Loewy. WHIT
had for long time been making a stud,
OF the problem. began q series of expert
nents. II may be interesting in this con
nection TO say that DR.. Loewy as IA
back As 1909 made several practical ant
highly successful tests at discovering tn
character OF tho minerals and orc beds II
German mines.
Varieties In EartA's Crust.
In the appMc,tio Of his principle
| these discoveries were made possibl
through the physical variety of the ma
| Insulators and conductors differ very ma
terially when acted upon by electrical
waves and electrical currents. Thus
, may be laid down a principle that non
conductors Of electric currents are con
ductors Of electric waves. while conduc
! tors OF the electric current will hinde
/ the passage OF electric waves.
Tho major geological formation OF tn
earth's crust fortunately simplihes 10
us the application Of this principle. Mos
stones, II they are water free, are In
/ sulators for conductors OF the electri
| current between ore beds and water. Dr.
B Loewys theory regarding the formation
OF the material OF the earth's surfac
/ leads to the conclusion that the insulator
and the buried conductors--that Is or
beds and water-must be made NANTES
1 through the employment of the electrical
| wave.
The we'll known comparison between tn
electrical wave and the light wave, whic'
was made by Maxwell and Hertz and who
! gave rise to the use In this connection o
such expressions as reflection, absorptic
and Interference, should be borne In min
/ in the study OF the electrical wave. FIX
perlments have shown that the conductor
| of electrical currents absorb electrical
! waves-that Is reflect them-whlle In
sulators OF electrical currents permit III
passage through them OF electrical wave
with undminished power.
The earth has long been looked upon q
a conductor OF electricity, a proof OF tn
being It's use for grounding telegraph
wires and burying the ends of lightning
| rods. Or. Loewy believes that by the EN-
ployment OF his new wireless wave ap
paratus for passing electrical wave
! through the earth's surface he will be abb
TO discover the internal structure OF tn
/ earth and detect the presence or eitne
water or valuable ore and mineral de
poslts.
Form Exploration Society.
Tho success that has attended the pre-