New-York tribune., 1907-01-18
GA TUN.


Gatrn appears TO be the cruX of the present
isthmian canal scheme, Cuebra was of De
Bessepss enterprise and az Boho was of the
second French essay, and 1t may properly be
reckoned the greatest of them all At Culebra
there was novel problem but merely the
excavation Of cutting precisely like innumer-
able others in the world. that 1t would be
larger than any Of them. At Bohio there was
the problem OF constructing a foundation
1875 feet below level a dam rising 100 feet
above level, which should create an arti-
fetal lake some miles in extent by impounding
the waters Of one of the most ungovernable
streams in the word-a river which sometimes
rises twenty feet in as many hours. Some men
were confident at early date that the Bohio
dam was quite practicable who later regarded
II as quite impracticabe.
The proposition at Gatun is much Ike that at
Bohio but much larger and more difficult. Gatun
is the point at which the line of the canal leaves
tho alluvial plains and swamps and enters the
hilly country. IT Is proposed there to dam the
Chagres River at point where it is very much
larger and more intractable than at Bohio. so
as to control its waters and to create huge
artificial lake which shall form part Of the canal.
This dam is to be about 100 feet long 100
feet wide AT the top and 1925 feet wide at the
bottom, and rising to 135 feet above sea level.
1t will impound lake l512 miles long. with an
area of ITO square miles and with depth or
more than 100 feet. Passage up and down this
dam will be effected by means of duplicate
flights of locks. each flight consisting either of
three locks of 2S1s feet lift each of two locks
of 421h feet lift each. Each lock will he large
enough to accommodate the largest ship in the
world
For such structures foundation is obviously
necessary The old idea was that bed rock was
the only satisfactory foundation. and when en-
gineers two years ago found no bed rock within
about 200 feet below sea level they regarded the
Gatun site impracticasle. Now the belief
is entertained that such dam need not be of
masonry resting directly on bed rock it may
be of earth and may rest upon earth. II Ia held
that a wall of earth half mile thick at bottom
and not less than 100 feet thick at the top
will he sufficient 10 mpOund lake. Certainly
many natural lakes are contained by no
stronger barriers. Nor is there thought to be
need of getting down 10 bed rock. The engi
neers find nj Gatun at a depth of fifty feet
thick stratum OF what is termed soft rock"
and is probably indurated clay and they
believe that will he good enough foundation
Probably few would question ii If that indu
rated clay extended downward 10 the bed rock
But that. apparently. il does not do. for there
is between it and the bed rock stratum or
softer material. perhaps of mud. The question
then arises whether that layer of soft rock Is
Slf1clentiE integral ana lmperNlouS 10 shN'di
the dam and locks and TO prevent the impouHded
floods from making a passage down to the
softer stratum below and thus perhaps under
mining the whole work.
II was only half a dozen years ago that lead
ing engineers declared that they had no doubt
at all about the practicahility Of the construc-
ton and operation Of the Rohio dam. Later.
because of more thorough examinations the
same engineers declared the Bohio project 10 he
impracticable. We must assume that. with
such lamentable experience in remembrance.
the engineers now in charge of the work have
Gatun than their predecessors did OF those Mt
Bohio There has in the last half dozen
years been a material advance in engineering.
Men are able to make more certain of things
now than they were and 70 do things which they
could not have done. So I may be that conf
deace is norv justified at Gatun although II was
not at Boho. "There fs." says the engineering
committee Of the Canal Commission. nothing
'in the later examinations made affecting the
.rracr!cabiltty or the perInanence OF the Gatun
"dari" Such statement would not, we as
srme he made by responsible men unless they
were themselves absolutely convinced OF IFS
correctness and II hv this time th" astlon could
not accept as trustworthy so measured and Ak
picit Judgment of the Canal CoLnGlissicn snd
its engineers. we should despair OF It's ever De-
ing able 20 trust ANYBODY IN connection with
the undertaking.