Year: 1872

REPORT OF ENGINEER, ROBELING-PROGRESs OF


TIE WORK.


The annual reports of the New-York Bridge
Company have recently been published, and contain
many interesting and instructive facts regarding inc
bridge now building between this city ana Brookyh'
ON the BROOKLYN tower the masonry has been carried 10
an elevation of 100 feet above high water ana UP 10 "
% feet of the roadway. Below the roadway NUMBER oil
heavy steel and iron bars will be set in the masonry Tor
variety of purposes They comprise six sets OF cast


steel bars ten by two inches and 60 feet long, passing
around the outside OF tower, between the masonry
courses and serving as an attachment lor the nam u
der floor storm cables In addition there are l6 sets oil
cast steel passing through the connecting walls ana
into the main butresses. To these will be attached the
six nes OF trnsses OF the bridge well as 6 counter
stays to the cables.


The iron bars comprise four smaller sets for underOOr
stays and 90 sets of long TO be laid In the connect
ing walls below the floor. They are all galvanized as
protection against rust Chief Engineer Roebling states
that the amount Of masonry and concrete laid on that
foundation during the past Winter, under water Is eqaI
In quantity TO the entire masonry OF the Brooklyn tower
visible to-day above the water line.


At the beginning Of the enterprise the tower founda-
tlOns constituted the principal engineering problem 10
be overcome, and not till they were accomplished iacts
could be sld that the project OF the bridge was placed
upon firm immovable footing. The subsequent build


ing OF the and of the superstructure Is all WORK
the tower foundations the stability OF the entire
work The whole enterprise depended ON their success



necessarily involved in their construction but these
have all been overcome.


The sinking of the NewYOrk casson was rendered pc
cuary unpleasant from the fact that Its location mad
for many years been the site of the principal dumping
ground for city garbage. The mud abOunded in decay
ing animal and vegetable remains Although the odOr
Of these checked while imOedded in the salt water
mud forth III its original strength when brought
in with the caisson air. More men were over
the material constantly covered with water, as TO
the odor it gradually disposed Of through the
water shafts


According to Mr.. ROebng the effect Of the compressed
air on the not serious first anticipated.
The few cases of death that occurred could in but
two instances be charged 10 the effects OF
the pressure. The fact remains, however, that
the effects OF compressed air on the human
system constitute the principal difficulty attending
cult to get wages are high, and the time Of labor
short that the work must necessarily be done
under disadvantage, and under immense amount of
supervision, where II Is at all difficult different from
ordinary digging in a uniform material


An ingenious mechanical telegraph used In keep
ing up communication between the upper and suUma.
rne world. In lighting the cass0n ordinary street gas
was the only agent used One interesting fact OBJ
servedthat in compressed air all gas-lghs become
sitve flames. answering to the stroke Of hammer
piece of irOn even to tones OF the voice.


Engineer RoeDling recommends the early acquisition
OF the ground required for at least anchorage
make beginning this season. and utilize the coming
Winter by putting In the foundation The quantity OF
masonry in anchorage is about the same In q
tower, although OF less costly character and more
easily put in place. Both the towers and the anchOrages
have to be completed before anything be done with
the necessary preparations for cable making