Robert Adam - Viaduct across the Low Calton

The Architecture of Robert Adam (1728-1792)

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VIADUCT OVER THE LOWER CALTON

Essay by Julian.Small

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Until the completion of the new North Bridge in 1772, the principal access from Edinburgh to its port of Leith had been through a "mean and squalid" suburb,¹where the butchers and cordwainers (leatherworkers) had their premises. This suburb, on the site where Waverley Station now stands, was hemmed in to the north-east by the steep slopes of Calton Hill, and the route to Leith lay through a deep ravine between Calton Hill and the ridge on which the Edinburgh New Town was laid out from 1767 onwards. The road along this ravine was called either the Low or Lower Calton, or St Ninian’s Row, and today forms part of Calton Road.

In 1791, it was suggested that Princes' Street in the Edinburgh New Town should be linked by a bridge to Calton Hill. Robert Adam made several drawings showing possible ways of doing this.
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The building of the North Bridge, however, had by-passed the Lower Calton, and traffic between Edinburgh and Leith now crossed the east end of Princes’ Street. The Edinburgh New Town had been intended as a purely residential suburb, with houses looking out to both north and south onto landscaped gardens. But whilst the houses to the north retained their essentially domestic character, along Princes’ Street to the south commercial interests fairly soon began to appear,² a process which has culminated in its being the main shopping street in Edinburgh.

By the beginning of the 1790s, this process was already under way. Robert Adam’s own Register House, the site for which was granted to the Trustees by the City Council in 1769, was not commercial in purpose, but neither was it residential. The terrace of houses which Adam designed for Leith Street on behalf of the Register House Trustees in 1785 contained some purpose-built shops in the basement storey, and it is recorded by the end of the 1790s that most of the premises at the east end of Princes’ Street were in commercial use. In addition, the City Authorities were proposing to develop buildings on the slopes of Calton Hill. The logical next step must have appeared to be the linking of the east end of Princes’ Street and Calton Hill, where the new Bridewell designed by Adam was soon to start building. And it would appear very logical that such a linking bridge should, like Adam’s unexecuted designs of 1785-6 for Edinburgh’s South Bridge (and like the completed scheme of 1785-8, which drew much from Adam’s project) be lined with shops and houses along the two sides. Such a bridge could also have led to join the road from the bottom of the Canongate which was the precursor to today’s A1, the Great North Road. The new bridge would have formed a magnificent triumphal entry to Edinburgh from the main route from the capital of the United Kingdom.

The Viaduct, seen from the north-east. The blank arches articulate what would otherwise have been very large expanses of blank masonry, and the windows would have provided light to storage vaults.
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The earliest suggestion that such a bridge should be built came from John Paterson in 1790.³ John Paterson was the Clerk of Works recommended by Robert Adam for the building of the new Edinburgh University, and was to be instrumental in gaining several commissions for him. It is known that it was at his suggestion that Adam was asked to provide designs for Charlotte Square, Edinburgh, and the fact that it was he who first promoted the idea of a bridge crossing the Lower Calton, leads to the inevitable conclusion that this design of Adam’s must relate in some way to Paterson’s advocacy.

The impressive design to which this computer model relates exists in only one drawing,⁴ a view from the north, showing a - somewhat idealised - perspective view of the ravine, with the viaduct seen side-on. The viaduct towers up out of the valley, with North Bridge and the dome of Adam’s Edinburgh University visible in the background to the right, and, beyond the left-hand end of the viaduct, an elaborated version of the monument designed by Adam himself to the philosopher David Hume, his personal friend. Further to the left is an Italianate design for the new Bridewell. It is a preliminary, sketch design, intended to impress his potential client, in this case Provost Stirling, and it is for this reason that a dedicatory inscription referring to Stirling, in the same fashion as the one above Adam’s entrance to Edinburgh University, is shown above the bridge arch. The drawing itself reflects Adam’s taste for landscape watercolours, with contrast between light and shadow and the dramatic qualities of the landscape setting, all of which provide parallels with Adam’s desire to present a sense of "movement" in his architecture.

The bridge which Adam designed is taller than the one which was built on the same site in 1815-22, which rises fifty feet high.
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The viaduct which Adam shows is much larger than would have been required to cross the ravine of the Lower Calton. The bridge which exists in the same location today is fifty feet high, and although Adam’s drawing is without any scale to provide precise measurements, the arch of the bridge is clearly taller than that. The bridge arch is flanked by two smaller, pedestrian, arches in a gigantic triumphal arch motif, with a further lunette arch above the centre arch, at the level of the roadway. The bridge abutments are shown with windows, suggesting that Adam intended to construct vaults beneath the approaches, perhaps to be used for storage in the same way as the vaults beneath the Adelphi development in London, designed by Adam 1768 onwards. To provide access to the lower range of vaults, Adam shows flights of steps, combined with terraces, rising up the abutments, and giving access also to Princes’ Street and to Calton Hill. It is unclear how access to the upper ranges of vaults would have been gained, but the drawing appears to show at least seven levels below the level of the street. The abutment walls are articulated with blank arches, pilasters and rectangular panels, since such large expanses of plain masonry would have appeared very "dead" to the eye. The rhythm which the blank arcade sets up gives movement to the design.

Adam showed flights of steps rising up each flank of the viaduct, from bottom to top. This would allow the abutments to be used for storage.
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The buildings flanking the roadway rise to five storeys height at the centre. From the centre block to the ends of the viaduct run ranges of two storeys with pavilions reminiscent of those at the ends of the blocks of shops on the Pulteney Bridge in Bath. Sections of these ranges - and, indeed, the base of the centre block of buildings - are opened out to form viewpoints, allowing views northwards along Leith Walk to the Firth of Forth and across to Holyrood Park to the south. These are a feature not present in Adam’s designs for South Bridge, apart from the opening between the buildings as the bridge crosses Cowgate, and show the importance of vistas in the 18th-century appreciation of landscape. However, they can be compared to the porticoes at the apex of the Ponte di Rialto in Venice, designed in 1588 by Antonio dal Ponte, which allow views of the river and canals. It is suggested that dal Ponte’s bridge, which was known to Robert and James Adam from their respective visits to Italy, influenced them in their designs for Pulteney Bridge in Bath,⁵ although here the only views that can be gained are through the windows in the rear walls of the shops. Andrea Palladio’s rejected design for the same Ponte di Rialto, which he described and illustrated in the third of his Four Books of Architecture, is a more immediate source of inspiration for Pulteney Bridge, and also has porticoes over the central arch.⁶

Sections of the buildings lining the bridge are opened out to form viewpoints, from which passers-by could look north and south.
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The inscription above the Lower Calton arch refers to "this bridge of shops and houses," but very little direct evidence is shown on the drawing as to how the street facades would have appeared crossing the viaduct. Certain assumptions can be made, and the computer reconstructions which have been attempted use the little evidence which is available. It is likely, on the analogy of Adam’s designs for South Bridge and for Leith Street, that shops would have filled most of the ground floor, with houses or apartments above. The buildings would be unlikely to have been very deep: the buildings lining Pulteney Bridge in Bath are only one room deep. However, the views available from such shops and houses would have given them an unrivalled location.

Above the Low Calton, Adam's drawing shows a panel with an inscription in honour of the Lord Provost in 1791, whom Adam hoped would commission the building of the bridge.

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Despite the over-scaling of the design, this proposal was not merely a fanciful dream, since it seems that Adam went to the trouble of commissioning a measured survey of the ravine, presumably employing the staff from his Edinburgh office to do it.⁷ A second design exists for a bridge across the Lower Calton, in this case with measurements attached.⁸ This design is in the same castle style which Adam used for many of his late country-house commissions, especially in Scotland, and which he also employed for the new Edinburgh City Bridewell, the foundation stone of which was laid on St Andrew’s Day 1791, and the design of which must have been one of the largest projects Adam undertook during that year.⁹ The new Bridewell was to stand on the top of Calton Hill, and both the bridge and the viaduct must have been intended not least to provide access to this new scheme. A further design which may relate to a third scheme for bridging the Lower Calton also exists,¹⁰ but only as a rough sketch and not, unlike the first two, with any inscription associating it with Calton Hill, although there is a - presumably later - pencil inscription relating it to the Cowgate in Edinburgh and hence to the South Bridge scheme. Like the South Bridge scheme and Pulteney Bridge at Bath, it is classical in style, and it too has buildings along the roadway. It is of much more modest dimensions than the Viaduct design.

The castellated design for bridging the Lower Calton is not only of more modest dimensions than the Viaduct which Adam had first envisaged. It also omits all the buildings lining the roadway. Like the bridging of the Lower Calton at the foot of the Viaduct, the main vehicle arch is flanked by two pedestrian arches, the former marked as eighteen feet wide and both the latter six feet. Again like the Viaduct design, steps descend the wing-walls of the bridge, presumably continuing (although this is not shown on the drawing) to the foot of the ravine. The roadway along the top has castellated parapets and, as is common in eighteenth-century bridges, four semi-circular pedestrian refuges above the main bridge piers.

It is not hard to find the reasons why neither bridge design was built. The outbreak of war with Revolutionary France, a war which was to continue almost without intermission until the Battle of Waterloo in 1815, was a serious setback for all building projects. Central government refused to spend money on building projects during wartime; public authorities of all kinds found it difficult to raise capital for construction works, and even private building was much affected. Some building projects, such as Edinburgh University, partly complete in 1791, had to wait until after 1815 for completion and - although not in Edinburgh - some speculative housing developments were abandoned for just as long a period.¹¹ Completion of the new Bridewell was a priority, whereas improving the access to it from Princes’ Street could afford to be postponed. In 1813-14, moves were made towards the construction of a bridge in this location, and in November 1815 Archibald Elliot was appointed architect, Robert Stevenson having already been appointed engineer.¹² Like Adam’s design, the bridge built by Elliot is lined with buildings. The difference lies in the fact that whereas in Adam’s design the buildings rise to their tallest in the centre of the viaduct, above the bridge, and there are viewpoints from the bridge abutments, in Elliot’s executed proposals it is the approaches to the bridge which are lined with buildings, and the arch bridging the Lower Calton which is surmounted by a screen of Ionic columns. This is very similar to Adam’s alternative design for the arch over Cowgate in his South Bridge scheme,¹³ and it is likely that Elliot had seen copies of Adam’s drawings for this, and quite possible that he knew of Adam’s scheme for the Calton Hill Viaduct. The buildings flanking the bridge approaches have five floors of basements below street level, and the arch of the bridge itself rises fifty feet above the Lower Calton. So big was the job that it was not finally completed until January 1822, construction of bridge and road across Calton Hill having cost almost £40,000, an immense sum.¹⁴ By comparison, construction of the South Bridge, with its nineteen arches, between 1785 and 1788 cost approximately £15,000.¹⁵ Only thirty years after his death was Adam’s vision of a monumental entrance to Edinburgh from the east realised in the Regent Bridge and - inevitably for that date - Waterloo Place.

The screen of Ionic columns on one side of Waterloo Place as it crosses Regent Bridge. The buildings flanking the approaches to the bridge, which rise from the valley below, are also visible.
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