The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1915-08-12
GEOLOGICAL GEODET|C
SURVEYORS IN IDAHO
WORK IN PROGRESS
METHOD OF coMMuNlcA-
TON AND OPERATION.

! 4. M. AIuoils, IA tI.e Lewiston 49,
lbuAe, gives Iue 1otiomlns aeGvuns
lnv JoniL "orh DeAns uoIle W ao.eln-
anent surveying pal.les as LoAons.
AIS suin4i4eI Doln t4Ie GA,Leo ,5sa.os
lcodst alu 6CouelAc survey 41aIu ,44o
CnALea STAGES seolVsIcal survey 04~
"oAAInS WESTWARD tnroukn tiI4s slato.
Dany messdses are DcIIis sent ose4
Jour neaus w LAe cvasl anu seuuel4S
survey party. Iness messages are seA.
Iby means vi acet ylene lamps az n4s44.
ana hellosraph Ny uay, Inc latter ue-
ing all arrangement oL mirrors Ior re-
|1Iecting the rays ot the sun III al4y
uesIreu alrecLlon, with the cVnllAen.e.l
formation about the Work are sent ue-
tween the observing party anu ugnt-
keepers.
=. V. Hodgson Is cnlet OF the survey
party in TINS stale and IN this section
EMANCIPATION is the work that is
being done by the survey.
lrlangulatlon Is an accurate deter
mination OF the distance and direction
between the various permanently
marked points OF survey scheme,
laid out on the surface of the earth to
cover certain area, without the ac-
tual measurement OF the various lines
by chain and tape. Triangulation is a
skeleton survey, and serves TO coordI-
nate and adjust the local survey with
their proper relation with the re-
mainder OF the surveyed portions of
the country. 1t Is done by measuring
with great accuracy the distances be-
tween two survey stations and also
measuring at each station the angles
between the adjacent stations Of the
survey scheme when by trigonometry
the distances between all the stations
I1may be computed.
Means of Communication.
If the latitude and longitude of one
station are known, and the direction
to another station either known OF
measured, the latitude and longitude
, lof each station may in turn be COM
Iputed.
The direction of the line joining the
, first two stations, or the azimuth OF
the line as 1t Is commonly called, Is
, found by observations on Polaris the
north star. Similar observations to
, check the directions are made at var
ious points as the work progresses.
In measuring the angle between sta
. lions, some Of which may be as much
as 100 or $50 miles from the observer
it is necessary to use lights at the var
: ious stations, each managed by light
keeper whose business 1t is to keer
, the light directed toward the observ-
I ers station. These lights are acety-
, lene lamp and Photograph as before
4 mentioned.
, To make 1t possible to see from one
, station to another, 1t is often neces-
sary to build towers higher than the
, Surrounding trees, or to enable the
: observer to see over some intervening
a obstruction. The choosing of stations
and construction Of towers is being
done by ]. s. Bilby, who is working
, ahead Of the observing party and the
Hight keepers.
In any locality which has been COW
cred by triangulation, many prominent
marks other than those specially pre-
pared are located for the use Of the
engineer and surveyors, such as the
Ichurch steeples, water tanks, belfrys
; on school houses and court houses,
; large prominent trees and other OBJ
Ijects. These are located by observa-
ltions from two or more stations on the
main scheme. Most Of the stations
Iare located on the high mountain
peaks, from which nearly all other
stations within range of $50 miles
can be seen.
Value of Triangulation.
Special care is given In marking the
stations, to secure them against de-
Istruction. The surface mark Is usual
lily small brass disc or copper ball,
loaded or cemented into hole in q
rock ledge or set in the top Of con-
crete post, while reference marks are
|set at various distances to assist In
finding the station.
AS soon as the field work Is COM
Ipleted a description Of each station,
with It's distance and direction from
|other stations, is published by the
lcoast and geodetic survey.
Triangulation, besides connecting
the various large public surveys
Throughout the country, is Of direct
Ibeneflt to many people in the terri
tory through which 1t is extended by
Its connection with the local land sur
veys and the city surveys. The stone
or concrete post set in the course OF
the work bears the same relation to
triangulation as the blazed trees and
corner posts bear to the ordinary land
surveys.
The survey started at Ogden, Utah.
and is being extended north and west