The New York herald., 1870-12-01
THE ST. LOUIS BRIDGE.
Tho Great Structure Across the Mississippi
Progress sf the Work-Efsscts Of Com
pressed Air ON the Workmen-
Lighting the Caisson.

Bridge Company BY Mr.. james Is. Eads, the chleI
engineer OF the structure which s to span the Mis-
sissippi river at ST. Louis, Ii Of considerable In
terest In connection with the like gigantic under
taking to span the East river between New York
and Brooklyn. We make the following extracts
from the report
The masonry OF the west abutment has been con-
pleted from the bed rock Of the river to = point
thirty feet above low water mark. From the bed
rock 70 Tue top Of the masonry tho height Is new
l0rty-lour feet. Eight courses OF granite are laid
On H. aud two courses, Ave feet are required to
complete II to the skewbacks against which the steel
ribs OF the span win rest This mass OF solid
masonry stands upon the lower edge OF che wharf
N st. Louis and measures ct It's base. In the dlrec
tion o the river current nnetyf0ur feet, and trans
versey sixy-two leet nine inches, and contains ~
this time $50 cubic yards OF masonry. When COM
above the bed rock OF the river aud will then con
tain II, $50 cubic yards Of masonry.
ane work on It s going steadily forward In salts
on ths 18th Of February. 1868, aser thoroughly
stone q the bridge was ans LAID IN II THIS abuaent y
hye feet below high water mark about four months
after commencing the construction Of the dam.
FILLING OF THE AIR CHAMBER.
inc Ming OF the ar-chamber with concrete COM
menced on the second day OF last March, ana was
being nfty three days. The space filed may DO
fairly stated ~ nearly 00o cubic eet The OF the
s p st s s q
soon as it touched the ned rock This Was ~ its
edge was eight inches from the rock. The northeast
corner was sixteen inches, and the southeast corner
eight inches. 1t will be seen from this that the rock
the edge or the caisson was removed tne rock land
bare aud the space filed carefully with concrete, the
infii,ration er the water under the edge Of the
caisson than could be managed by the pumping
Tangements within It, The sand seemed packed so
firmly tnat no trouble was taken to barrcade 1t out
OF this space between the rock and the edge OF the
casson. When the entire edge OF the caisson ana
the space under It's two great girders thus
creted. the rock in It's nerer gradually cleared
Of sand and the concrete placed directly upon IL in
courses under the roof Of the chamber being souty
rammed In place. The alr-locks were then filled
with the same material, ana finally the shafts. The
concrete was made OF broken limestone thoroughly
washed, the interstfces beng filed with mortar
made OF equal parts Of Akron cement and pure
sand.
EFFECT OF COMPRESSED AIR ON THE MEN.
The first symptom manilesting Itself, caused by
the pressure Of the air. IL pannncss in one or both
ears The Eustachan tubes extending from the
back OF the mouth 10 the bony cavities over which
the drums OF the ears are distended are SO minute
through them to these cavities, and when the pres
sure Is Increased rapidly the external pressure on
e % pam .S eoes G snc
metric changes as occur in the atmosphere IN which
we live. The act of swallowing facilitates the pas
pressure on both sides OF the drums and prevents
the pain. The pressure may be admitted into the
In all cases relieve 1t. BY closing the nostris be-
tween the thumb and fingers shutting the lips
tightly and innanng the cheeks, the Eustacnian
tubes are opened and the pressure on the inner and
the pain prevented. Fhis method must be
is let on II Il be increased rapidly No inconyen.
tence Is felt BY tho reaction when the pressure u
les or as the oppressed air within the drums has
tendency TO open the tnbes, and thus facilitates It's
escape through them. whereas Increasing the pres
sure has the efrect q osllapslng them, and there
1ore makes II moro diicul 70 admit the compressed
air within the cavities Of the ears. II frequently
eccure however. from some abnormal condition OF
tncsetubes. q! when nnamed by Q cold In the head,
that neither Of these remedies will relieve the pain.
10 continue the admission OF compressed ar int
the lock under such circumstances would intensity
therefore the lock tenders were particularly in.
structed 10 shut or the compressed air at the mo-
the ears. ana tnen il could not be relieved BY the
above means, the lsck was opened and the person
ber. Sometimes aiteen minutes were occupied In
passing persons through the first time afteI
which they usually had no further trouble from this
the fact that the depth penetrated by the air.
chamber was considerably greater than tnat hith-
any benefit from the experience or Others In either
guarding against any Injurious effects OF this great
tolt. or Of awaiting myself or any known speclnc
for relieving those affected BY 1t. When tine depth
men were affected BY muscular paralysis Of the
lower limbs This was rarely accompa MED with
PAIN and usually passed on In the course OF day
two. As the penetration or the pier progressed the
paralysis became more dinicult to subdue. In some
cases the arms were involved and In few cases the
sunered much pain In the joints when the symptoms
were severe. An average OF at least nine out OF ten
o1 those aGeStea saaessa no pam 6pt
The duration Of the watches in the air-chamber
was gradually shortened from four hours to three,
and then to two and finally to one hour.
The use Of gslvanlc bands or arnor seemed, In the
opinion Of the Superintendent Of Construction the
marksble immunity from these attacks. They
were oil ultimately provided with them. These
bands were MADE OF alternate OF Zinc and si
yer, and were worn around the wrists, arms ankles
and waist and also under the soes or the feet SUI.
hcent moisture and acldity were supplied by the
armer, and rs the opinion OF those most accdstoms
to the chamber was almost unanimous In favor OF
tins remedy am very much inclined ito believe 1t
Immediately on the manifestation OF greater Sc.
verify In the symptoms q hospital boat was ntted
the city DIR. A. Jaminetj was engaged to attend
those affected. and also to institute such sanitary
M q ss @ Saa n6a n care
Of every workman was daily made, ana none were
permitted to engage In the work without the ap.
were sent te the City Hospital and had the
benedt of the advice and treatment OF Its
humber Of men epoyed in the arcSamber Of this
pier was 1862. or this number about thirty were
seriously affected. Notwithstanding the care aud
skill with which those most severely attacked were
treated twelve OF the cases proved fatal. Each
OF these without exception believe, was made tho
suDect ol Dy the coroner AIDED Dy
autopsy conducted usually by some OF our most
sKiTul surgeons and physicians While the excit-
Ing cause in all OF these cases was doubtless the ex
posurc OF the system to the pressure OF the con-
densed air OF the chamber the habits and condition
OF several OF those who died were, at the time they
went to work, such as would have excluded them
net aud the verdict In about one-har or the cases
gave totally different cause for the death OF the
patient. Nearly or quite all OF these deaths hap
pened TO men unaccustomed to the work; several
vi them 10 men who had worked but ono watch OF
two hours In contrast 70 this Is the fact that quite
large number OF the mcn-certainly one
half Of those constantly mpoyed-commenced
with tho work at It's inception and remained
throughout its continuance entirely without injury
or Inconvenience.
The gentlemen composing the engineer corps OF
the bridge all visited the airchamber, some OF them
sonal duties or nom motives Of curiosty and none
OF them suffered any Injury whatever
Much diversity Of opinion was expressed by the
inms hsH rtns,a. wn0 ~. .ro nacassaS