The Daily bulletin. [volume] (Honolulu [Hawaii]) 1882-1895, 1884-11-06
THE BRITISH SCIENTISTS-N0. 8.

After the address of Sir +. j.
Bramwcll, +. II. S., on 1.-The Tri-
umphs of Engineering" in the me-
chanical science section, summa-
rized in our last number. Mr.. Ben
jamin Baker presented Il paper on
the great bridge to be built across
the Firth of Forth, Scotland. We
quote:-
He mentioned that five tenders
were submitted for the work, the
amounts varying from fl, ,4S7, 900
sterling to f2, ,30l, ,7GO, and that the
contract was finally let to Messrs.
Tancrcd. Arrol & Co., on the 2lst
of December, 1882, for fl 600, 900,
which was within f5, 900 of the esti
mated cost of the work as prepared
by Mr.. Fowler and Mr.. Baker him
self for Parliamentary purposes.
The total length of viaduct included
in this contract is about one and II
half miles, and there are two spans
Of ZOO feet each, two of G75, 10 of
l6S, and five of % feet each. In
Guiding piers there is thus almost
one mile Of main spans and half II
mile of viaduct approach. The clear
headway under the centre of the
bridge is 80 feet above high water,
and the highest part of the bridge is
SCI feet above the same. Each of
these main piers consists of group
Of four cylindrical masonry and con-
crete piers, forty-nine feet in dia-
meter at the top and from sixty feet
to seventy feet at the bottom. The
deepest pier is about seventy feet
below low water, and the rise of
tide is eighteen feet at ordinary
springs. In the piers there are
about 100000 cubic yards of ma
sonry, and in the superstructurc
about 45, 900 tons of steel. Opera
tions were begun in January, 1888,
so the works have now been some
twenty months in progress, and
about fl70,000 have been expended
in plant and temporary works and
100000 in the permanent works of
the bridge. At South Queensfery
an area of about twenty acres of
ground has been laid out in shops
and yards for the manufacture of
the 200 foot span, four cylindrical
iron caissons constitute the lower
portions of the main piers Of the
bridge. At Inchgaryie stores and
offices have been built, and as this is
an exposed island in the middle of
the Firth the staying for the pier
work is of iron, pinned to the rock.
Mr.. Baker also stated the present
condition of the work, and described
in detail, with illustrations, the
whole structure. In conclusion, he
spoke of the interest taken in this
bridge by Continental and American
engineers, and of the anxiety felt by
those concerned.
This was followed by a paper from
Mr.. j. Clarke Henshaw, on the
Severn Tunnel Railway, which is
reported as follows:---
In former days, he said, one OF
the coach roads between England
and South Wales crossed the Severn
near the place where a railway tunnel
is now being made. Later on, when
railways were introduced, passen-
gers had to leave the train and cross
the river by steam ferry-boat. The
inconvenience9of this journey is in
creased by the great rise Of tide,
amounting mt times to over 40 feet
to do away with this break in the
railway communication between the
two parts of the country tunnel is
now being constructed. The work
was begun in March, 1873, and NO
great difficulty was encountered until
the driftway under the river was