The Irish standard., 1892-04-30
8A MAMMOTH STRUCTURE.
The Wonderful Accomplishment OF
Mechanical Science.
How the Great Building for Manufactures
and Liberal Arts at the Worlds Fair
Was Planned-A Monster
Derrick

1t is in it's present stage of construc-
ton that the mammoth building for the
manufactures and liberal arts at the
worlds fair is most curious and inter-
esting, says ,Harper's Weekly. They
are now at work on the big derrick, or
'''traveler,' as it is called, and the dimen-
sions Of this engine are suggestive of the
tremendous proportions the building
itself will assume as it nears compile
ton. The great Eads bridge at st.
LOFTS is remarkable structure, and
one would fancy that building con-
tanning more iron and steel than that
embraced in it's mighty arches must be
a rare building indeed In the manu-
features building will be used 400 tons
more Of metal than the amount used by
Mr.. Eads' engineers. New Workers
know what Brooklyn bridge looks like.
With the metal to be used in the liberal
arts building two such bridges could be
built, and there would still yennain as
much as 2.4OO tons unused. TO be more
exact, upwards Of 100000 pounds of
steel and iron will be consumed by the
constcuctionists in the work of putting
the liberal arts hall together.
The plans for this the most extensive
building ever attempted by man were
prepared by Mr.. George B. Post, Of
New York The trusses that will sup
port the roof are the largest iii the
world There will be clear span Of
1856 feet FROM pillar to pillar. When
the New Yorker stated that span of
this proportion would be used, archi-
tects and builders generally laughed at
the idea, and said that this was ideal
construction. But the enterprise was
not submitted solely TO builders of
houses. 1t was a point that was not all
Included in the studies of architecture.
It more nearly approaches bridge Ell
gineering. This is true of more than
one building planned for the Columbian
exposition. The bridge engineers were
consulted, made their calculations, looked
wise, closed their eyes as if in deep
thought, and then pronounced: 1T can
be done, but it will cost great fortune
in dollars"
MIR. Post was indicated, and the
worlds fair treasurer undertook to do
the rest. 'lhe contracts were let TO a
Pittsburgh company, and now they are
demonstrating the accuracy of the
mathematics by literally doing the work.
But there was another problem (and
not d small one) tt, be solved before the
iron aud steel were made ready. Given
Che plans ard the material, how could
this 5000 tons Of metal be lifted into
position? There are &c main trusses,
each weighing 200 tons, and these are
10 form the bases for the roof spans.
10 lit "a mass of material weighing 200
Sons. and TO handle it with the pre-
cision and accuracy necessary for the
nicetics Of Mr.. Posts plans, require nc
corn,non enginery. And no common
enginery is brought into play here. 1t
was q month ago that the builders be-
gar the work Of constructing the engine
which was to carry these immense
masses Of metal as easily as an athlete
swings Il duln',~bell. 1t was now almost
hnished---a derrick 255 feet in height,
and 36S feet in length. 1t is built with
four uprights at the corners, that are
iointcd ct sections Of 40 feet by heavy
srcss beams, making the skeleton. For
we stays are tlSsti stS ropes VI olecA t1ls1L
are strung diagonally. Then there are
Y trusses that, being bottled and
mort;sed TO tho cross beams, insure the
strength OF the structure,
The ''travcler" rests on founda ton
as stable and as solid as may be.
strip of the great floor was torn up, and
piles in three rows were driven in along
the line Of the track which the derrick
is to follow Caps Of timber IL inches
square, on which are placed 100-pound
steel rails, make track. Purchase will
be had in the great cranes that will be
rugged on the top Of the traveller
The heaviest tackle obtainable will be
used in the working of these cranes A
stationary engine will be used to move
the derrick along tha track.
Now that this great derrick is ready,
it is expected that the building itself
will grow rapidly. In this case the prep
aration for the work is almost as great
an un dertal1ing as the work itself.
IRELAND AT THE FAIR.