252 Mr Stevenson's Description of Bridges of Suspension. 
neration in the execution of many works of a similar nature. 
The trustees for this bridge;, with proper liberality, have pre- 
sented Captain Brown with 1000 guineas since the completion 
of the work, over and above his estimated price. 
Design for Cramond Bridge.— Fig. 5., in Plate VIII., is 
descriptive of a plan which was originally intended for crossing 
the river Almond, on the great north road between Edinburgh 
and Queensferry. The extent of the span between the points of 
suspension here, is laid down at 150 feet. The chief circum- 
stances which particularize this design, are a mode of fixing 
the catenarian chains to the abutments of suspension on each 
side of the river, and in dispensing with that part of the piers 
which rises above the road-way, by which the main chains are 
unavoidably prevented from being distributed equally under 
the road- way. The main chains are likewise made to collapse 
or turn round the abutments of masonry, as will be seen from 
the section in which the parts of the work are so contrived, that 
access can be had to the chains, by an arched way on each side, 
marked d on Fig. 5. In this design, the two ends of the catena- 
rian chains are formed into great nails or bolts, with counter- 
sunk or conical heads made to fit into corresponding hollow tubes 
of cast-iron, included in the masonry of the abutments. 
From this description, the reader will readily form an idea 
of the simplicity and effect of this mode of fixing the chains, 
being such, also, that any particular chain may be withdrawn 
and replaced, without deranging the fabric of the bridge. The 
roadway, instead of being suspended from the main chains, is 
made up to the proper level upon the catenarian chains, by a 
frame work of cast-iron, prepared for the reception of a stratum 
of broken stones for the road. 
The making up of the roadway of this bridge, however, 
and the enlarged angle of its suspension, may be considered 
as limiting the span or extent of bridges of this construction, 
to about 200 feet. The structure represented by Fig. 5. 
appears to possess many advantages for bridges of that mo- 
dified extent, and the manner of fixing the catenarian chains is 
applicable to all bridges of suspension ; it is likewise new, so far 
as we know. 
Strength of Iron.— T he writer of this article has had oc- 
