FOUR PENCIL DRAWINGS OF PROPOSED SUSPENSION BRIDGES ACROSS FOUR DIFFERENT POINTS OF THE AVON GORGE, SUBMITTED TO THE COMMITTEE OF THE SOCIETY OF MERCHANT VENTURERS OF BRISTOL IN THE FIRST COMPETITION TO CHOOSE A BRIDGE, EACH DRAWING SIGNED ("I. K. BRUNEL") AND DATED NOV. 19TH 1829. The four scale drawings are numbered 1-4 in the upper left hand corner of the page. Each drawing consists of two "Figures," an elevation or section of the bridge in the upper part of the page with a ground "plan" below showing the crossing point over the Avon, the course of the river and the cliff contours, scale 12in. to 500 feet, sheet size 24¼ x 36½in., each sheet mounted on linen and preserved in a rolled up green cloth portfolio stamped "Clifton Suspension Bridge" in large gilt letters.
"Drawing no. 1," showing a bridge on top of the cliffs with a Romanesque arch at each end, conforms with what Isambard Brunel, in the biography of his father, I. K. Brunel, describes as "the first design ... for a bridge of 760 feet span between the points of suspension" with "a height of 215 feet above high water mark" and "towers 70 foot high" which "would have had to be built on the cliffs to carry the chains" (The Life of Isambard Kingdom Brunel, Civil Engineer, 1870, pp. 47-48). In contrast to the other three drawings, there is no attempt to delineate the scenery, woods and buildings, below the cliff face. Isambard explains that his father "did not approve of this design, as the situation was not favourable to architectural effect, a point to which the committee attached great importance; but he suggested it from its being somewhat more economical than other plans."
In the same chapter on "The Clifton Suspension Bridge," Isambard then refers to "another design ... some way further down the river" for which "towers would also have been necessary" and in which "the distance between the points of suspension was 1,180 feet." This in fact appears to be "Drawing no. 4" in the portfolio, headed "Section at DG," where the crossing point is at the farthest distance down the Avon beyond the spot marked on the plan as "Nightingale Valley." The towers themselves have no form of ornamentation and look rather more like solid blocks.
What Isambard describes as his father's "two remaining plans" and "the most interesting of the series," with a distance between points of suspension of 980 and 1,160 feet respectively, are consistent with Drawing nos. 2 and 3 in the portfolio, headed "Section at DI" and "Section at DE." These were I. K. Brunel's preferred plans. "The site selected was one where the rocks rise perpendicularly for a considerable height above the proposed level of the bridge, and therefore piers and land-ties were dispensed with, the chains being hung directly from the rock. No masonry was required for architectural effect" (p. 48). The two elevations are at different crossing points, no. 3 being further down river than no. 2. In both drawings the turrets at bridge level and castle keeps above are in the "Norman" style which the biography mentions. "Drawing no. 2" has the tunnel at only one end of the bridge and an archway through the rock at the other, and this is described as the one major difference between nos. 2 and 3. Although it may not appear clear from Drawing no. 3 that it is actually intended to have, as Isambard states, a tunnel at each end, this drawing is reproduced in the biography (plate 1, opp. p. 49) and the reproduction, though much reduced, conforms exactly with the drawing we have.
Isambard's account of how his father's suspension bridge designs came into being has formed the basis of all subsequent biographies, and remains the authoritative text. In the early part of his chapter, the biographer explains how:
"For the remainder of the year 1828, and during the greater part of 1829," his father "was without any regular occupation, until, in the autumn of 1829, he heard that designs were required for a suspension bridge over the Avon at Bristol, and he determined to compete.
"This project originated in a bequest made in 1753, by Alderman William Vick, of the sum of 1,000l. to be placed in the hands of the Society of Merchant Venturers of Bristol, with directions that it should accumulate at compound interest until it reached 10,000l., when it was to be expended in the erection of a stone bridge over the river Avon, from Clifton Down to Leigh Down ....
"In 1829, when the fund amounted to nearly 8,000l., a committee was appointed to consider in what way it would be possible to carry out Alderman Vick's intentions. An estimate for a stone bridge was procured, but as it gave the cost at 90,000l., it was evident that this scheme must be abandoned.
"The committee then advertised for designs for a suspension bridge. Mr. Brunel, on hearing through a friend of the proposed competition, went to Bristol; and, after examining the locality, he selected four different points within the limits prescribed by the instructions of the committee, and made a separate design for each of them. His plans were sent in on the day appointed, Nov. 19, 1829, with a long statement...."
Of twenty-two plans submitted for the competition, only those of Brunel and four other competitors were put forward for the ultimate judgement of Thomas Telford who, it is well known, rejected all of Brunel's proposals on the technical grounds that the maximum admissible span for a suspension bridge was 600 feet, declared there was no winner, and then made himself an entrant for the second competition, this time won by Brunel. That these four drawings for the first competition are signed and dated November 19th, 1829, which, as the biography confirms, was "the day appointed" for the submission of entries is still further evidence that they are the very same designs which came under Telford's scrutiny. They are, of course, no longer accompanied by the "long statement" or report which Brunel submitted with them, and on which his son was able to draw for technical specifications in the biography.
Drawing number 2 is affected by a tear, while Drawing no. 3 has a repaired tear right across the middle of the page, and it seems likely that the drawings were mounted on linen and bound up, probably a short time after the competition, to prevent further deterioration. The drawings have, for a long time, been regarded as lost and their re-emergence into public light is an exciting event for Brunel scholarship.