The Barre daily times. (Barre, Vt.) 1897-1959, 1907-11-11

Supplies There Secured Are Among 'hs
Hest for An Purposes

Best for All Purposes
The very general ballet that wells
sunk IN granite viii get no weteF ".
pears not unreasonable whfn we epnp'',,e ..
that granite il the hardest q t"NNs
and that "a surface ouferops are ~
rule 20 free from pore. q sIsessss
/ through which water might clfep'aee
that the expectation Of finding water w
drilling would seem absurd. WITHIN tre
last few years. however, the many sue.
eessful wells driven IN crystalline Foens
have effectively proved the erroneous
character 81 the Old opinion.
The conditions controlling occurrence
Of water In crystalline rocks have ~
Gently been studied by T. y. klnt "
connection with an extensive inyestlsa'
ti0n OF the underground waters q Lpn'
nertlent, and hy Frederick q. Inpps
whose field of work has been Maine =
brief article by AIR. Ellis was pubiisnca
by the United States geological survey
h water.supply paper No. 100. Mt
Clamps detailed report a still ~ manu-
script bnt will be published IN ie"
months. The following paragraphs sum.
maFixe his results 20 far a. they feiAte
70 waters IN granite.
The crystalline rocks, such a. granite,
gnelsses, schists, etc, ike the sesllnien-
tary shales. iimeatones, and andtoneh,
carry water IN their porc--the pierosco.
PIC spaces between The grains Of Aohd
matter, but while the sedimentary rocks
may absorb several per cent. Of Their
volume in water--sa ndstones about 70
per cent, lmestones 5 per cent? ana
shales per eent.-granltes and other
crystalline rockssrarely absorb wafer 70
more than half Of ! per cent. OF
their volume, and the water IN SUCH
rocks moves through tho pores 70 slowly
that Il can never escape fast enough 70
be Of value In wells Fortunately, how.
ever. the crystalline rocks are trasersed
IN various directions by many joints and
crcvices. An investigation Of these joints
shows two principal systems, one Of
which Is nearly vertical and the other
horizontal. The vertical joints, which
may be hundreds Of feet In length, while
not al all regularly spaced. arc usually
10 10 % feet apart, trend in all direc.
lions. aud me be inclined 20 the vertical
n any angle up 20 70 degrees. The dis
lance between the horizontal or sheet
Joints. which approximately parallel the
surface, varies from a few Inches near
the surface 20 many feet az q depth OF
several hundred feet below.
The nearly vertical joints serve as
channels for the admission Of water from
the surface, while the sheet joints form
reservoirs for It's storage. As most OF
the joints are rather narrow, the amount
81 contained water IA likely 20 be mod
crate, and the yield Of wells In granite
Is seldom more than 10 gallons a min.
ute. though some exceptional wells,
pumped By steam. have yielded as much
as 80 gallons q minute. Out Of " sue
cessful wells In southern Maine, only
two yielded more than 80 gallons :
minnie.
The extreme irregularity Of the Joint
systems makes the success OF any well
in granite a matter Of chance. OF two
wells drilled within so feet Of each other,
one may be failure, the other marked
success Records collected in southern
Maine indicate that about 81 per cent.
Of the wells drills in granite supply
water enough for ordinary domestic
uses
The depth TO which drilling should be
carried in granite. as indicated BY the
investigations made both in Maine and
Connecticut, has a maximum limit Of
about 200 feet, below which the chances
OF success diminish rapidly. Mr.. Clapps
records show that out OF II wells re-
porting the principal water horizon, IL,
or more than one-third. found II within
80 feet Of the surface; 10 more, OF over
one-half OF the remainder. reached It
within 100 feet Of the surface; z, or ex-
actly half Of the wells more than 100
feet deep, tapped their principal supply
between $50 and 200 feet and only 1
wells, or so per cent of the entire num-
Der Of recorded wells In granite over 200
feet deep. obtained II from lower depths.
Granite water, where not contaminated
by surface drainage, Is excellent for
and is probably satisfactory
for all other uses ordinarily made Of
water
As to the cost, which Is necessarily
an important factor In the sinking Of
wells. the price for drilling six.inch wells
In granite on the coast Of Maine ranges
from "a to Sc foot, the higher figure
being the more common. The cost Of
drilling granite wells and blasting open
wells in the same rock is in some Sec
tions Of Maine the same for either tyne
SO a foot. It's freedom fro the great
danger Of pollution, common to all open
wells, makes the drilled wen in every
case preferable.