More and more, the use of iron was being generally accepted as a technical necessity in the forties. At Buckingham Palace Blore, in adapting one of Nash’s side pavilions as a chapel for Queen Victoria in 1842-3, used visible iron supports just as Nash had done so long before in the interiors of the Brighton Pavilion for her uncle. Yet generally the use of iron in important masonry structures in the thirties and the early forties was quite invisible, being confined to the floors and the substructure of the roofs. In 1837-9 C.-J. Baron (1783-1855) and Nicolas Martin (1809-?), for example, provided a complete iron roof above the vaults of Chartres Cathedral, a work of very considerable scale and technical elaboration that provided the immediate prototype for the iron roof of Gau’s Sainte-Clotilde in Paris, designed in 1840 and begun in 1846. At the Houses of Parliament, the actual construction of which started only in 1840, Barry capped the whole with iron roofs—the external iron plates are actually visible, of course, but the fact of their being of iron is rarely recognized. Fireproof floors built according to various French and English patent systems were increasingly thought necessary in all high-grade construction. Queen Victoria’s Osborne House on the Isle of Wight, constructed without the aid of an architect by the builder Thomas Cubitt, had them throughout, as did many other well-built country houses of the forties, at least in the passages and stair-halls. Here and there in the commercial buildings of this decade the iron skeleton used inside came through to the exterior, as it had on one of Rickman’s Liverpool churches a generation earlier. A small office building at No. 50 Watling Street in London, with visible iron supports and lintels in the upper storeys but with brick corner piers and brick spandrels, was a case in point, probably dating from early in the decade. By 1844 Fairbairn was recommending in a report that fireproof construction should be used in all warehouses. Increasingly this was done in Lancashire and, before long, elsewhere; Fairbairn himself had introduced it ten years earlier in the Jevons Warehouse on the New Quay in Manchester.