ANNUAL ADDRESS. XI. 
I am indebted to Prof. W. H. Burr, for the complete set of 
drawings exhibited of one of his draw bridges, which is built over 
the Harlem River Ship Canal, and provides two clear openings 
of 104’ each; also, to Mr. Theodore Cooper for the view of the 
drawbridge designed by him for the Suburban Rapid Transit 
Company over the Harlem River. I have described and discussed 
these bridges mainly for the benefit of the Roads and Bridges 
Department and others who may have to design draw bridges, 
because I consider that in this direction there is much to be learnt 
from America, and our own practice may be very greatly improved. 
I saw nothing in England or Europe to compare with the bridges 
mentioned, and the more recent bridges such as those over the 
Manchester Ship Canal are decidedly inferior. 
There is a great bridge under discussion at the present time in 
New York which is proposed for crossing the Hudson River 
between Fifty-ninth and Sixtieth Street. The total distance to 
be bridged is 3,200’ and two designs have been submitted by Mr. 
Charles McDonald which possess considerable merit, viz., a canti- 
lever bridge with a central span of 202’ and a suspension bridge 
of 311’ span. Each of the main piers of the cantilever bridge 
which are twoin number, are built of steel, having four main 
members rising in parabolic curves from its bases, each of which 
form a square in plan measuring 200’ on each side, up to another 
Square of 80’ side. The bases at each of the four corners rest on 
Cones, which are carried by four steel tubes, each 80’ in diameter, 
sunk in the bed of the river to a depth of 210’ below high water 
and filled with concrete. The section of the tubes forming the 
Piers is of box section 15’ square, the height of the pier is 536’ 
above high water and the top of the supporting cone is 30’ above 
high water. From the piers the main span starts, and in three 
equal bays covers a space of 2,300’ between centres of towers. © 
The headway is 150’ above high water. ‘The floor of the bridge 
is curved to a parabolic form in a horizontal plane, and is 140° 
Wide at piers, and 80’ in the centre. The upper tension members 
are parallel throughout. The central truss carried by the cantl- 
