240 Mr Stevenson’s Description of Bridges of Suspension. 
way of this bridge is suspended between two abutments or 
towers of masonry, 37 feet in height, on which piers of carpen- 
try are erected, which are 35 feet in height. Over these ten 
chains are suspended, each measuring 516 feet in length, their 
ends being sunk into deep pits on both sides of the river, where 
they are secured by large stones. The bridge over the Meri- 
mack has two carriage ways, each of fifteen feet in breadth. It 
is also described as having three chains, which range along the 
sides, and four in the middle, or between the two roadways. The 
whole expence of this American work is estimated to have been 
20,000 dollars, and the bridge calculated to support or carry 
about 500 tons. 
Proposed Bridge at Runcorn. — Perhaps the most precari- 
ous and difficult problem ever presented to the consideration of* 
the British engineer, was the suggestion of some highly patriotic 
gentlemen of Liverpool, for constructing a bridge over the estu- 
ary of the Mersey at Runcorn Gap, about 20 miles from Liver- 
pool. The specifications for this work provided, that the span 
of the bridge should measure at least 1000 feet, and that its 
height above the surface of the water should not be less than 
60 feet, so as to admit of the free navigation of this great com- 
mercial river. The idea of a bridge at Runcorn, we believe, 
was first conceived about the year 1813, when the demand for 
labour was extremely low, and a vast number of the working 
classes of Lancashire were thrown out of employment. A varie- 
ty of designs for this bridge were procured by a select committee 
of the gentlemen who took an interest in this great undertaking. 
The plan most approved of, however, was the design of a bridge 
of suspension; and Mr Telford the engineer, and Captain 
Brown of the Royal Navy, are understood pretty nearly to 
have concurred in opinion as to the practicability of such a 
work. Mr Telford has reported fully on the subject, and has 
estimated the expence of his design at from L. 63,000 to 
L. 85,000 according to different modes of execution. Though 
as yet little advancement has been made in carrying this en- 
terprising design into execution, yet the novelty and magnitude 
of an arch of 1000 feet span, is a subject of so much interest, 
that we have thought it proper in this place to mention these 
circumstances. 
