- 
May 9, 1884.] 
The shore abutments are at A and F, nine hundred 
and ten feet apart. The piers B and E, having a 
width on top of twenty-five feet, support two trusses, 
A B C D E F 
195’ | 175’ 120/ 175/ 195/ 
A Cand D F, the lengths of whose arms are marked 
below them: on their outer ends rests the independ- 
ent truss C D, one hundred and twenty feet in 
length. The parts B Cand D Eare the cantilevers, 
carrying the truss C D, and projecting from the piers 
B and E as a bracket from the face of the wall. 
The ends A and Fare prevented from rising, under 
any load between B and E which may not be balanced 
by the excess of weight in A B and E F, by anchor- 
ing bolts at A and F, extending to iron beams placed 
beneath the shore abutments. These abutments 
SCIENCE 
073 
June 26. The masonry on the American side was 
finished Aug. 20, and on the Canadian side Sept. 3. 
The two towers or steel piers, each of which has 
four legs, sixty feet by thirty feet apart at the base, 
twenty-eight feet by twenty-five feet apart at the top, 
one hundred and thirty-two feet high from the top of 
the masonry to the bottom of the truss, and thor- 
oughly braced in all directions, were begun Aug. 29, 
and completed Sept. 18. A 
Scaffolding or false-works for the support of the 
portions A B and EF F having been put up, these 
shore-arms were built upon it in the usual manner 
of bridge-erection, and were finished in time to begin 
construction of the river-arms on Nov. 1. ‘This 
portion of the bridge was built out, piece by piece, 
triangle by triangle, from the piers, with no other 
outside support than a travelling framework above 
and projecting forward from the bridge itself: this 
THE CANTILEVER-BRIDGE OVER THE NIAGARA RIVER. 
weigh one thousand tons each: the maximum lifting- 
force to which either one will be subjected is three 
hundred-and forty tons. The expansion and con- 
traction from changes of temperature are provided for 
‘between B and £ by joints at C and D which allow 
longitudinal motion, and at A and F by pendulum 
links which permit a similar movement. 
A detailed statement of the rate of progress in 
construction and erection will show quite clearly the 
advance made in late years in the art of bridge- 
building, and the ease with which structures of the 
American type, jointed at intersections and con- 
nected by pins, can be put together. The contract 
for the bridge was signed on April 11, 1883; and a 
clause was included by which the builders would 
forfeit five liundred dollars per day for all time re- 
quired to finish the structure after Dec. 1. Ground 
was broken for the foundations of the towers, April 
15. Laying of the concrete foundation, eight feet 
thick, began on June 6; and of the masonry piers, 
thirty-eight feet high and twelve feet square on top, 
traveller carried a suspended platform to insure the 
safety of the workmen. The sections from the two 
shores were built out and joined Nov. 21, without 
serious accident or delay. The track was down, 
ready for a train, in seven months and a half from 
the beginning of the work, and with eight days to 
spare on the contract time. 
The bridge has two trusses, twenty-eight feet apart, 
fifty-six feet deep over the towers, twenty-one feet 
deep at the shore-ends, and twenty-six feet deep at 
the mid-span. Ample wind-bracing is provided. 
The material used in the towers and heavy compres- 
sion members is open-hearth steel: most of the other 
members are of wrought-iron. One admirable point 
in the design of the engineer, Mr. C. C. Schneider. 
and in the way in which it was executed by the 
builders, the Central bridge-works of Buffalo, N.Y., 
was the fact that no piece, while the bridge was in 
process of erection, was subjected to a strain greater 
than, or different from, what it must undergo in the 
completed structure. At the formal test and open- 
