To the mid and late forties belong several splendid examples of mixed construction in various countries that not only represent technical feats of a high order but are also fully architectural in character. Some are by architects, others by teams of architects and engineers working in close collaboration. In building the Britannia Bridge,[[167]] which crosses the Menai Strait near Telford’s Menai Bridge, the Derby Trijunct team of Stephenson and Thompson in 1845-50 utilized with great success the rectangular tubes built up of wrought-iron plates that Fairbairn, the consulting engineer, recommended (Plate [61]). The Holyhead railway line still passes through these tubes. The masonry entrances and the tall towers, taller than they need have been because of Stephenson’s original intention to use suspensory members for additional support to his rigid tubes, were superbly detailed by Thompson. Contemporaries called them Egyptian, but the design has already been noted as fully consonant with Romantic Classicism though quite devoid of Grecian elements. At least the sculptor John Thomas’s pairs of gigantic lions at the entrances are Nubian!

At the London Coal Exchange[[168]] built in 1846-9 in Lower Thames Street, the City Corporation’s architect Bunning arrived at no such complete co-ordination of masonry and metallic design as did Stephenson and Thompson on the Britannia Bridge. The masonry exterior consists of two palazzo blocks set at a fairly sharp angle to one another and loosely linked by a very Picturesque round tower, free-standing in its upper stages. Behind all this the dome of the interior court can barely be glimpsed. Inside this court, however, no masonry at all is visible; one sees only an elegant cage of iron elements rising to the glazed hemisphere above (Plate [63]). The metal members are richly but appropriately detailed, and there is even more appropriate decorative painting by Sang in such panels as are not glazed.

In France two monuments of comparable distinction have already been mentioned, Henri Labrouste’s Bibliothèque Sainte-Geneviève of 1843-50 and Duquesney’s Gare de l’Est of 1847-52 (Plate [22B]). Unfortunately the original shed of the latter, with arched principals of 100-foot span, was taken down when the station was doubled in size in the present century. Inside the library a central row of iron columns of somewhat Pompeian design—that is, resembling the slender, metallically scaled members seen in Pompeian wall paintings—still carries the two barrel roofs on delicately scrolled arches of openwork iron (Figure [14]). Since the masonry walls with their ranges of window arches are visible all round, the effect produced is less novel than in the iron-and-glass court of the Coal Exchange; but Labrouste achieved much greater integration between interior and exterior (Plate [21]). The Dianabad in Vienna, built by Karl Etzel in 1841-3, had a fine iron roof; the circular bracing of the iron principals, a frequent motif in large openwork members of cast iron at this time, was most appropriate to the Rundbogenstil detailing of the masonry walls (Plate [66B]).

Monferran’s cast-iron dome on St Isaac’s in Petersburg, completed about 1842, has already been mentioned (Plate [27A]). This was rivalled before very long by several American examples,[[169]] most notably Walter’s enormous dome, built in 1855-65, above the Capitol in Washington (Plate [82A]). Baroque in silhouette and rather Baroque in detail also, this may have encouraged—along with the rising taste for elaborately plastic effects of which it was itself a notable expression—the increasingly common practice of casting the exposed iron elements of American commercial façades in the form of rich Corinthian columns and heavily moulded arches.

Around 1850 cast-iron architecture was coming to its climax everywhere. James Bogardus (1800-74), a manufacturer of iron grinding machinery, not an architect or engineer, began to erect in Center Street in New York in 1848 a four-storeyed urban structure for his own use as a factory with an exterior consisting only of cast-iron piers and lintels. This was one of the earliest[[170]] and most highly publicized of the cast-iron fronts which Bogardus and various other ironmasters in New York and elsewhere made ubiquitous in the principal American cities before and after the Civil War. But his earliest completed iron front was that of the five-storey chemist shop of John Milhau at 183 Broadway erected within the year 1848. An extant work by Bogardus, the range of four-storey stores built for Edward H. Laing at the north-west corner of Washington and Murray Streets in New York, was begun in 1849 and finished within two months, well before his own building was completed. These early cast-iron fronts are very logical and expressive in the way the attenuated Grecian Doric columns and flat entablatures are used to form an external frame; but the Laing stores have lost most of the applied ornament that appealed so much to mid-century taste (Plate [67B]). Later façades are richer and heavier, generally with Renaissance or Baroque arcading, as has just been noted. For the Harper’s Building in New York built in 1854, which incorporated the first American rolled-iron beams, the architect John B. Corlies provided a design of ornate Late Renaissance character. Curiously enough, in executing this building Bogardus used for the upper four storeys the same castings as in the Sun Building that he had erected in 1850-1 in Baltimore to the designs of R. G. Hatfield (1815-79). To the typical cast-iron fronts of New York,[[171]] of which the most extensive and one of the simplest was that of the old Stewart Department Store on Broadway begun in 1859 by John W. Kellum (1807-71), vacated several years ago by Wanamakers and burned during demolition in 1956, one may well prefer the delicacy of a Glasgow example, the Jamaica Street Warehouse[[172]] of 1855-6, or a remote Far Western department store like the Z.C.M.I. of 1868 in Salt Lake City, rivalling amid the Rocky Mountains those of Paris. Neither of these is the work of architects.

Great Britain and Europe saw few all-iron façades. This was in large part because the danger of their collapse when exposed to the extreme heat of urban conflagrations, a danger made real to Americans only by the fires of the seventies in Boston and Chicago, was appreciated very early. Yet it was not in America but in Britain that the greatest masterpieces of iron construction of the fifties were built. The succeeding turn of the tide against the visible use of iron also had its origins in Britain, not in America where the material had early become so tediously ubiquitous.

In 1850 Paxton was completing at Chatsworth a relatively small new greenhouse to protect the Victoria regia, a giant water-lily imported from Africa by the Duke of Devonshire. With its arcaded walls of iron and glass and its flat ridge-and-furrow roof, this seemed to Paxton to provide a suitable paradigm for the vast structure[[173]] needed by May 1851 to house the Great Exhibition, the first international exposition, which was scheduled to open at that time. The Commissioners of the Exhibition had held an international competition that produced several extremely interesting ferrovitreous projects, notably an Irish one by Turner, Burton’s collaborator at Kew, and a French one by Hector Horeau. Rightly or wrongly, all of them were rejected, and the Commissioners’ own Building Committee, including the chief architectural and engineering talents of the age, then produced a project of their own. Reputedly in large part the work of the engineer Brunel and the architect T. L. Donaldson (1795-1885), this manifestly impractical scheme, a sort of Rundbogenstil super-railway-station intended to be built of brick—the project actually provided the inspiration for Herholdt’s Central Station in Copenhagen of 1863-4, or so it would appear—was already out for bids when Paxton presented in July 1850 his own scheme based on the Chatsworth Lily House. Published in the Illustrated London News and offered with a low alternative bid by the contractors Fox & Henderson, this was accepted and—with much significant modification—erected in the incredibly short space of nine months.

Figure 14. H.-P.-F. Labrouste: Paris, Bibliothèque Sainte-Geneviève,
(1839), 1843-50, section

Inside this vast structure, with its tall central nave, galleried aisles, and arched transept, Paxton and his engineer associates, Sir Charles Fox (1810-74) and his partner Henderson (to the two of whom a considerable part of the credit must go), created unwittingly a new sort of architectural space. So large as in effect to be boundless, this space was defined only by the three-dimensional grid of co-ordinates which the regularly spaced iron stanchions and girders provided (Plate [64]). These elements, designed for mass-production, and also in such a way that they could be disassembled as readily as they were assembled, had a new sort of mechanical elegance towards which the design of metal components had hitherto been moving only very gradually. The character of the casting process made it only too easy to impose on cast-iron elements all sorts of more or less inappropriate decorative treatments from Gothic to Baroque; only rarely had stylistic detail been successfully reinterpreted, as by Bunning in the Coal Exchange, in terms of the fat arrises and broad radii that are suitable to the material and to the particular method of its production. Even at the Crystal Palace a few touches of ornament provided by Owen Jones (1806-89), who was also responsible for the highly original and rather Turneresque colour treatment, suggest the gap—and, alas, it was in the 1850s a widening gap—between the technicians’ and the architects’ ambitions for iron.