The sun., 1909-06-21
TEE hattie or THE LEVELS.
light on tho Possibilities and Cost oi
Subaqueeus Excavation.


To TIE EDITOR OF THE SuN-sir. In tn,
May number OF tho Outlook were publishec
an article Of Mr.. John r. Freeman defending
the actual lock and lake plan and another
by myself defending the ~Straits Of Panama.
Mr.. Freeman Acknowledges. a. everybody
10 authority has done. that the Straits Of
Panama type 10 the complete solution OF
the problem, but he seems to believe thst
its realization can be effected only - Z
dream becomes = reality. II is easy te
establish that the dream hiss become Z
tangible reality.
! Mr.. freeman says at ths beginning Of his
article: The Straits OF Panama type = I
once built would bs all right but will have
to wait until the dream OF its one
sponsor comes true, that this 1sthmian rock
{can somehow be shattered under water and
| dredgsd rapidly at one-tenth the prioe .
cubic yard now estimated by Colsnel
ooethsls and the other experienced engi-
peers."
Mr. Freeman has very clearly defined his
position. The Straits OF Panama. are all
right from every point Of view II the shat
tering Of rock is made at low cost.
About the perfection Of the straits when
built Mr.. Freeman shares the opinion OF Mr..
Alfred Noble. the preemipent. sponsor OF
the perpetual lock canal. who said last Feb
ruary before the alumni Of Stevens Insti-
tute: Such . broad channel ut sea level a.
the one advocated by Mr.. Bunau-Varilla
and by him appropriately designated "a
Straits OF Panama would afford quick er
and safer navigation than any possible lock
or sea level canal
Mr.. Freeman also shares tho opinion
onacially expressed in 1905 by Mr.. Taft as
Secretary Of War In favor OF 0 sea level
canal half the width OF the Straits of
| On L..
President recommending the actual lock
canal proposed by the minority OF the con-
sulting board: we may well concede that
II we could have q sea level canal with q
prism 800 TO 400 feet wide, with the curves
that must now exist reduced. Il would be
| preferable TO the plan OF the minority. "
From such words may be inferred what
is the opinion Of Mr.. Tsft for channel 500
feet wide at the bottom and 900 feet wide ct
the water level.
Therefore the opinion Of Mr.. Freeman is
In strict accord with that Of the head OF the
State, with that OF the head OF the lock
canal school about the perfection Of the
Straits OF Panama type II once made .
reality.
Mr.. Freeman adds: 1T would not have to
wait. IL would be an immediate reality II
the Isthmian rock could be shattered at
one-tenth the price Colonel GoethAls and
other experienced engineers estimate It..
but such thing 10 dream"
Here are the eSperime entail facts which
formed my opinion. Whether they lead
to scientific knowledge or to dream will
be Judged easily.
In 1885. when at the head OF the works
OF Panama. was suddenly confronted with
the necessity Of removing rapidly q mass
Of rock under water near Colon.
V- ~. -
practice consisted In having the rock blasted
and removed by mon working In compressed
air caissons. The cost was seven or eight
times higher than In the dry. / had no
plant Of this kind on the Isthmus. I thought
then that II the rock could be broken in
pieces - large a. mans head. by dynamite
put In holes drilled from the surface Of
the water. the dredge would have made
no difference between such loosened rock
and material naturally loose. The experi-
nsnt succeeded admirably. and the cost
proved to bs about that of the open air
excavation.
Some time later a contractor, Mr.. Jacob.
having to open the channel through the
rocky hills OF the Mindi between Colon and
Gatuu) and who was paid ut the price OF
dry excavation. did not hesitate. In view
Of the results Of the experimental work
I had done. to abandon the dry excavation
and TO sxcavate the rock below water level
by dredsfne. II he then dreamed, II vas
not . nightmare. because he often said to
me that he had made much money out OF his
contract. II could now hesitate to believe
recollections Of twenty-fonr years ago
would be sure not TO dream threading on page
ISL Of the Canal Record OF April z, 1905. the
following: From the shore1ine to the hills
At Mindi the work Ii being done by dredges.
har
expensive, Is done here for less than 81
q cubic yard. Holes are drilled In the
rock. which is blasted without springing.
with 90 per cent. dynamite. This blasting
has been done so successfully that the rock
Is shattered into pieces small enough TO be
handled by the ladder and dipper dredger. +"
The standard price for excavation In the
dry soft rock fixed by the international
Consulting Board In 1906 for the present
plan Ia 81 a cubic yard Nobody therefore
can be called q dreamer n he says that to-
day the very same method. invented and
employed twenty-four years ago for sxcs-
walton OF subaaueous soft rock, Is result
ing In cost inferior to that Of the excava-
tion in the dry exactly as It did at the same
place quarter Of . century ago.
1t may deeply surprise a laymsn TO see
such a fact put next to the valuation Of
subaqueous rock excavation made by the
International Consulting Board In 1905, or
next to that Of the Isthmian Canal Commits
sion In 1901. The most experienced engi-
neers Of the board fixed that price at q. So
The most experienced engineers of the COM
mission put 1t at N.7s The fact that the
work 10 now done at less than 81 by the old
method proves once more that In enRi-
neerng science the men most experienced in
a general sense may lack experience on .
special point.
My old method Of 1885 IL now obsolete,
and enormous strides have been made since.
unless when saying this / am the victim Of
a dream.
Soon after the cost Of exca walton OF soft
rock had been made about equal In the dry
and In the wet by the new method started
In Panama. the necessity OF deepening the
rock section Of the Suez Canal came to the
front. The directors OF the canal wanted
to avoid the use Of dynamite on the canal
Mr.. Lobnits, prominent dredse builder OF
Renfrew. thought of applying the new
method Of dredging rock. but OF break Ing
the rock without the use OF dynamite. He
revived an ancient process used In the har-
Dor Of Cette forty years before and which
consisted In breaking the rock by the fall
OF mass OF steel.
The system has gradually developed since
1888 into . perfect and very economical
method Of breaking the rock and making
II dredgeable by conclusion.
The cost OF less than one dollar for the
soft rock OF the Mndi Hills. which by