SARAH GUPPY AND HER BRIDGE PATENT No. 3405, 1811 [Guest article by Julia Elton]

Image of Sarah Guppy: by Stewy [with kind permission of Sheila Hannon, Creative Producer]

Sarah Guppy (née Beach), later Mrs. Coote. Baptised 1770, died 1852

Sarah Guppy’s modern reputation rests almost entirely on the mis-interpretation of her 1811 bridge patent. As a result, she has been promoted as the precursor of the modern suspension bridge and the true designer of the Clifton and Menai suspension bridges. However, these claims stem from a mis-understanding of the difference between the hanging bridge of her patent and that of the modern suspension bridge. The following piece puts Sarah Guppy into the context of her own time, rather than looking at her achievements through the distorting glass of myths that have been circulating about her since the mid-19th century.

Sarah Guppy was born into a family with interests in the brass and sugar trade and married Samuel Guppy, a successful Bristol merchant in the brass and copper trade. No doubt this background stimulated an interest, unusual for a woman of her period, in civil and mechanical engineering. The patent, her first, is headed, ‘Bridge and Railroads’ with a sub-title:

“A new mode of constructing and erecting bridges and railroads without arches or sterlings, whereby the danger of their being washed away by floods is avoided.”

It is very slight, only about 350 words, with no drawings and no technical details.


The bridge was site specific to the Bristol River Avon upstream of the Gorge, as revealed in Guppy’s efforts to promote it. Bristol’s communication with its hinterland, particularly North Somerset, had always been hampered by the fact that the mediaeval Bristol Bridge in the heart of the city was the only crossing of the Avon. Although William Vick in 1756 had suggested a bridge across the Gorge from Clifton to Leigh Down and William Bridges in 1793 had actually designed one, all the early 19th century designs, of which Guppy’s was the fourth, were intended to cross at river level near Hotwells, upstream of the Gorge.

The Avon has one of the highest tidal ranges in the world and it was impossible to found piers or protective starlings1 in the centre of the narrow channel. Any pier would have been in constant danger of collapse from the powerful tidal movement of the river. Furthermore, the river runs between exceptionally high mud banks, presenting challenging foundation problems. These conditions necessitated a single span of between 200ft and 300ft, greater than was achievable by arched bridges. In the context of 1811, Guppy’s patent outlines a reasonable way of dealing with such constraints.

Her bridge was formed of ‘several strong metallick chains, parallel to and at suitable distances from each other’. Above these chains she proposed laying:

“longitudinally and crosswise such fit pieces of timber, or iron, or other suitable material, as shall and may constitute a platform, which…shall afford a proper support for a road or pavement.”

Whereas a modern suspension bridge has a deck hung from an overhead suspending system using iron chains, Guppy designed a bridge with an underlying support system upon which the decking planks and surfacing were laid.

incan type rope suspension bridge

Incan type rope bridge

Bridges of this type had been used since ancient times in China and South America to cross deep and impassable mountain valleys or wide rivers, though generally using ropes of some kind. The deck necessarily follows the curve of the underlying cables, inevitably resulting in a sagging roadway, but since such bridges were intended for pedestrians, this did not matter. Guppy may have thought that using iron chains rather than ropes constituted a new and patentable element. She certainly understood that a flat, rigid deck was needed to carry the heavy loads of moving vehicles, and to achieve this specified that the ‘said chains may be drawn tight by secure mechanical means’, though she does not indicate how this was to be done.

In order to provide anchorages for her bridge, she intended to:

“drive a row of piles, with suitable framing to connect them together, and behind these I do fix, or drive, and connect, other piles or rows of piles and suitable framing, or otherwise, upon the banks of the said river or place, I do dispose or build certain masses of connected masonry or other ponderous structures, with piles or without, in order…that the said piles or masonry or other structures, shall be capable of sustaining and permanently resisting the action of a considerable force applied or exerted in directions tending to bring the same together.”

This is the opening statement of the patent and has led several commentators to assume she was patenting piles, although piling has been used at least since Roman times to build foundations in soft or unstable ground.

In order to understand her thinking, it is necessary to see this passage as describing a complete entity. Traditional hanging pedestrian bridges were lightweight and the supporting ropes could be tied round trees or fastened to rocks. Guppy recognised that her heavy iron chains would require far more substantial anchoring, both to maintain flatness and rigidity and to resist inward pull. Her solution was to provide huge masses of masonry set upon a forest of piles to ensure stability in the ground conditions of the Avon’s mud banks, though it is impossible to tell from her description exactly what form these structures were to take or how the chains were to be fastened to them.

Like all those taking out patents, she attempted to cover every eventuality. She mentions in passing that the masonry could be built without piles, presumably making it suitable for construction on rock, and that the anchorages could be made of ‘other ponderous structures’, a baffling statement unless she meant cast iron. These statements enabled her to claim that:

“no kind of ground is unsuitable for the foundation they may be erected in the most difficult and almost inaccessible places…and are alike applicable to every situation.2″

Of particular interest is her inclusion of ‘railroads’ in the patent, again presumably thinking that this was a new and patentable element. In 1811 she meant waggons drawn by horse, not by steam locomotive, running on iron plateways or edge rails. These horse-drawn ‘railroads’ were prevalent in nearby industrial South Wales. This is the weakest aspect of the patent because it is extremely hard to see how the deck, even tightened by ‘secure mechanical means’, could ever be rigid enough to ensure a reliably flat surface on which to lay the rails or plateways.

As soon as it was registered, Guppy’s bridge design was recognised as derivative by The Repertory of Arts which stated that:

“This method of making passages across rivers is of very ancient invention, having been practised in China from remote ages; and also in Peru and Mexico, as may be seen in the many histories and accounts published on these countries…Politeness might forbid us to question the ingenuity of a lady, and therefore we presume she must have been ignorant of these well known facts, or she would not have declared this mode of constructing bridges to be her own invention.3″

However, she may have thought that the concept of the such bridges could be modified to meet the problems of such a difficult crossing by using man-made rather than natural materials.

Whatever the case she promoted her patent vigorously. In 1811 the Monthly Magazine published a letter in which she described the advantages of the bridge, notably its ability to withstand flood conditions.4 She approached John Matthew Gutch, editor of Felix Farley’s Bristol Journal, who reported that ‘Mrs. Guppy has been assiduously employed in forming the model of a bridge to be erected across the Avon, from the Hotwells to the opposite side.’5 A few days later Gutch published a letter of support from ‘A Visitor and Admirer of Clifton’, who described seeing models and drawings of the bridge in London and indicated that there was talk of opening a subscription list. 6 Nevertheless, Guppy’s bridge fared no better than its predecessors owing to the crippling costs of building new approach roads. The Avon was not to be crossed at low level until the construction of the Cumberland Bridge road system in 1964.

Sarah Guppy was certainly the first person to patent a hanging bridge to take both road and rail traffic. However, the patent appeared at the moment when a completely new and far more effective type of structure was emerging. The American, James Finley, in 1801, first came up with the idea of a true suspension bridge, hanging a deck, via a series of stiff vertical hangers, below a suspending system using iron chains running over tall towers to their anchorages; this ensured a horizontal platform able to take wheeled vehicles. However, not until the publication of Thomas Pope’s book, A treatise on bridge architecture, in 1811, which carried a detailed description, did news of this development arrive in Britain. Meanwhile, Samuel Brown and Thomas Telford, unaware of Finley’s designs, had also been experimenting with suspension bridges. Brown made a prototype model in 1813 and in 1814 Telford produced a design, though it wasn’t built, for a suspension bridge of 1000ft span to cross the Mersey at Runcorn Gap. In 1820 Brown completed his Union Bridge over the Tweed. Designed specifically for vehicles, this was the first modern suspension bridge in Britain. It was followed by Telford’s Menai Bridge, opened in 1826. Guppy must have realised that her hanging bridge was completely superseded by these developments.

In 1812 she was granted a second patent (No. 3549), this time for a method of boiling eggs within a standard tea or coffee urn which also incorporated the means to keep toast warm. Again, it is quite brief and has no drawings. However, it may have met with some success since in 1824 she was mentioned in a satirical poem, entitled, ‘The Idler’s Epistle to John Clare’, published in the Bristol Mercury. The last verse reads:

“And thou shall have a jocund cup

To wind thy spirits gently up,

A stoop of hock or claret cup,

Once in a way;

And we’ll take hints from Mistress Gupp***

The same glad day.”

A footnote states:

“***The lady’s name is Guppy; but the rhyme was inexorable, and said Gupp. She is immortalised by the invention of a machine to keep muffins hot over the lid of a tea urn.7″

After this second patent, many years were to pass before she formally took up her interest in engineering again, producing in 1831 a far more substantial patent (No. 6186) with drawings and detailed descriptions of improvements to bedsteads.

Sarah Guppy and Suspension Bridges – putting the story straight.

Thomas Guppy plaque

In 1829 I.K. Brunel was in Bristol for the Clifton Suspension Bridge competition and met Sarah Guppy’s son, Thomas Richard Guppy, a powerful Bristol business man. At some point Brunel was introduced to Sarah, recording in his diary for October 1833 that he ‘returned to hotel calling on Mrs. Guppy on my way – a shrewd woman’. Guppy enthusiastically promoted the Clifton Bridge, writing anonymously in the Bristol Journal in 1832 that it was ‘a most suitable investment for ladies’.8 The following year she wrote a long letter, signed “G”, to the Bristol Mercury in July 1833, which opens:

“I am rejoiced to see by advertisements, that the suspension bridge is again made an object of attention; and most sincerely hope that every one will exert himself to contribute and procure pecuniary aid without delay.9″

Her support was clearly appreciated because she and her son, Thomas, were both asked by the Bridge Trustees to use their influence to chase up two defaulting subscribers.10

Avon gorge showing all that was ever built of IKB's design for bridge   1821_Avon_Gorge_Toward_Clifton_Danby

Left: the only parts of Brunel’s bridge design that ever got built.

Right: Avon Gorge in 1821 looking upstream towards where Sarah Guppy’s design would have bee situated.

The myth that Sarah Guppy was really the originator of the modern suspension bridge first reared its head with an article in the Bristol Mercury in August 1836, a week before the foundation stone for the Clifton Suspension Bridge was laid. The article cites the 1811 letter Guppy wrote to the Monthly Magazine promoting her patent, before continuing:

“We understand that the Menai Bridge was constructed by permission (which was asked) on Mrs. G’s principle, and that she is one of the most liberal supporters of the bridge about to be erected across the Avon at Clifton.11″

At this point Guppy was in partnership with William Henry Somerton, proprietor since 1829 of the Bristol Mercury,12in the editing, printing, publishing, and vending’ of the paper.13 It is thus almost impossible not to believe that she either wrote the piece herself or at least condoned its content.

This piece of ‘puffery’ was followed up in December 1839 by an even more mendacious article in the Bristol Mercury. Headed, ‘From a Correspondent’, it states:

“It appears to be forgotten that the public are indebted to Mrs. Coote…for the idea of Suspension-Bridges; fortunately for that lady, her public letter to the Editor of the Monthly Magazine, of May 1, 1811, inserted in that work…mentions her having taken out a patent for the same…Sometime after, gentlemen waited on Mrs. G. to ask her permission to use her patent in the erection of the Menai Bridge, and requested to know what they should give her for such permission; – when she, with her accustomed liberality, said it was at their service without any remuneration whatever. We understand that several considerable improvements for public utility are about to be brought forward by her, very shortly.14″

Although the partnership with Somerton had been dissolved in December 1837,15 after her marriage to Charles Eyre Coote, she presumably maintained her ties with the newspaper and it seems likely that once again she wrote the article, or at least condoned its exaggerated claims. Alternatively, Coote, her second husband, over thirty years younger than she was and a gambler, may have been the nameless ‘Correspondent’? Did he hope that her supposed association with Telford, who had died in 1834, might encourage success and financial remuneration for the ‘several considerable improvements for public utility’ she was about to register under the Copyright & Design Act? Alas, by 1843 the Cootes were so short of money that they were sued by the Clifton Bridge Trustees as defaulting subscribers, owing £260 on shares worth £400,16 particularly ironic considering that only nine years before Guppy was herself asked to pursue defaulting subscribers.

Even her obituary in 1852 continues the myth, stating that, ‘she early enunciated the principle of suspension bridges, for which, as long ago as 1811, she took out the first patent ever granted’.17

The inflated and incorrect claims that have been made in recent years for her engineering talents, particularly in regard to the bridge patent, have obscured a more interesting story. She was very well-read and was the most prolific female borrower of books from the Bristol Library Society in the years up to 1811 and no doubt beyond.18 She read many books in French, including the works of Rousseau and Montesquieu, and works on French history, including Biographical Anecdotes of the founders of the French Republic and Hereford’s The History of France, from the first establishment of that Monarchy to the present revolution. She was also a competent enough Latinist to read such works as the Argonauticorum of Apollonius Rhodius in the 1777 edition edited by John Shaw as well as De rebus gestis Alexandri magni of Quintus Curtius Rufus in the 1724 edition edited by Snakenburg. She also liked travel writings, borrowing Brydone’s Tour through Sicily and Malta, Sir John Barrow’s Travels in China, J.G. Stedman’s Narrative, of a five years’ expedition, against the revolted negroes of Surinam [etc]. and Thicknesse’s A year’s journey through France and part of Spain. She read a lot of literature and poetry, some theology, a little medicine and some natural history, though no works on natural philosophy or practical engineering. Her wide-ranging tastes and interests deserve to be looked at more closely. The fact that she was in partnership with the editor of the Bristol Mercury, however she may have used her role in this capacity, is surely unusual enough to be worth investigating further. She invested heavily in the Great Western Railway, buying 50 shares at a cost of £100 each.19 For all these reasons and despite the fact that none of her inventions appear to have had any practical application or financial success, she clearly had considerable talents and deserves to be looked at in a more measured way.

(c) Julia Elton 2019


Sarah-Guppy plaque



I invited Julia Elton to contribute this article as a guest blogger, because Sarah Guppy’s story is frequently used as an example of a very early British “woman engineer”. I have been guilty of this myself in the past.

As Julia makes clear, Sarah was both more and less than this but it is hard to justify applying the label of “woman engineer” to Sarah. Exaggeration and hagiography are unhelpful, even to prove a point that women can be and have been engineers. In excusing my own faults in this respect when I first started researching women in engineering, now over 15 years ago, the information on such ‘hidden histories’ is now becoming available online which would previously have required visits to distant archives and specialist libraries. Contacts from other researchers who happen upon one’s work online and who offer new insights is another great boon of the internet age.

I am most grateful to Julia Elton for so generously sharing her expert research on this topic.
Nina Baker


1 Perhaps the most famous starlings were placed around the piers of Old London Bridge. They protect the foundations of piers from scour. Sometimes they are brick or masonry and sometimes timber. Guppy’s patent spells them ‘sterlings’.

2 Letter to the Monthly Magazine, 1st May 1811.

3 The Repertory of Arts, Manufactures and Agriculture, Vol. XIX, 1811, p. 242.

4 The Monthly Magazine, 1st May 1811

5 Felix Farley’s Bristol Journal, 27th July 1811.

6 Felix Farley’s Bristol Journal, 3rd August 1811.

7 Bristol Mercury, 23rd August 1824

8 12th May 1832

9 6th July 1833

10 Letter to Thomas Guppy, 24th December 1836. BRO 12167(42), p. 108.

11 Bristol Mercury, 20th August 1836.

12 Obituary in Bristol Mercury, 1st October 1870.

13 Notice of the dissolution of the partnership, London Gazette, 5th December, 1837, p. 3224.

14 Bristol Mercury, 14th December 1839.

15 London Gazette, op.cit.

16 Bristol Mercury, 9th December 1843.

17 Bristol Mercury, 28th August 1852.

18 Bristol Library Society Register, Nov. 23rd 1808 – Sept. 30th 1811. Bristol Central Library, B7480-B7482.

19 Great Western Railway Company, Stock and Shareholders Records.  Alphabetical register of shareholders, A – G. National Archives. Rail 251/19.

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