Sect. II.
Class 7.
INTRODUCTION.
This Class embraces a variety of objects directly or indirectly connected with the purposes of construction.While the preceding had reference to the personal or domestic wants of mankind, this occupies a wider field, andincludes contrivances adapted to the preparation of public works, as well as of private dwellings, and embracesthe sciences of architecture and civil engineering in their most extensive sense. The general title of the Class,“ Civil Engineering , Architecture, and Building Contrivances,” sufficiently indicates its extent and defines itslimits.
The following subdivisions include all that can be properly said to belong to this department of the Exhi-bition :—A. Comprises Foundations and Building Contrivances connected with Hydraulic Works, such as Pilesand Pile-driving, Coffer-dams, Diving-bells, Boring Tools, &c. These are necessarily represented by modelsonly, or in great part, as the works themselves are of too great magnitude for exhibition. B. Scaffolding andCenterings for the erection of Chimneys, Columns, Towers, Bridges , &c.; Portable Scaffoldings, Ladders, Fire-escapes, &c.; Centerings for Arches, Domes , Vaults, &c. C. Forms an important subdivision, comprehendingBridges, Tunnels, and Engineering contrivances for crossing ravines, &c. D. Relates to Dock, Harbour,River, and Canal Works. E. Lighthouses and Beacons. F. Roofs, Buildings, and contrivances for coveringlarge areas. CL Water-works, and the Engineering contrivances connected with the obtaining, storing, anddistribution of Water in towns. H. Gas-works, and contrivances connected with the economical productionof Artificial Light . I. Sewerage, Cleaning, Paving, and the contrivances connected with the sanitary conditionsof towns. J. Warming and Ventilating Domestic Residences, and contrivances for such purposes.
Objects in this Class are found in the Building at the western end of the North Gallery, and also in the Areasand Avenues partly occupied by Classes 5 and 6 in the Ground-floor, North side. Several beautiful modelsconnected with this Class have likewise a place in the Central Avenue or Nave.
Containing a number of costly and beautiful models of many of the great triumphs of civil engineering andarchitecture, this Class presents an interesting view of the state and capabilities of the sciences it represents atthe present day. Among the objects included under the subdivision of Bridges , &c., will be found some of themost elaborate and accurate models probably ever constructed. Some of these are so minutely correct, that itis stated that even the threads of the screws are reduced to a scale. Tubular, suspension, and other bridges, arerepresented by some of these models, which are on a large scale. Chain-piers, and piers of other descriptions,each indicative of theis applicability to the particular purposes for which they are designed, or to the positionsoccupied by the originals, are also exhibited in their models. The application of iron chain-cables to purposesof this kind, and its history, are recorded in this Catalogue and illustrated in the Exhibition. A variety otbridges on new principles, or upon new modifications of principles already known, are also shown, and theirrespective merits are capable of being ascertained in the models.
Dock and harbour works are also adequately represented by their respective models. Among others is amodel of the Breakwater in Plymouth Sound, executed in limestone, and presenting a favourable idea of thagreat work. The lens-apparatus of lighthouses, in most recent and improved forms, is exhibited not by modelsbut by the apparatus itself. A large number of models are of works proposed to be executed, and convey astrong impression of the various directions in which inventive skill is exercised. Interest will be excited bymany well-executed models of structures in cast and wrought iron. The application of these metals to the pur'poses of construction, so largely illustrated in the Exhibition Building itself, forms an important feature in thehistory of modern architecture, and is also represented by various models of conservatories, such as the greaPalm-house at Kew, roofs of railway stations, &c. The miscellaneous contrivances connected with tfisimpler construction and arrangements of private dwellings are found in great numbers. Many of these rela eto ventilation, to windows, doors, and chimneys, and appear to promise improvements of importance in thesrespects. ... , 0 f
The study of this Class is instructive, as the means of attaining an approximate idea of the present state athe sciences of civil engineering, architecture, and construction in our own country. The objects illustra 1 athe Class can scarcely be said adequately to represent the subjects embraced by the Class, since they ^ ose , • 0advantage of being seen of their due dimensions. While in Class 5 it is possible to exhibit the actual mac iengaged in raising the Britannia Tube to its site, in the present Class the Tube itself, the most w0 ?“ e L z eengineering structure of its kind, can only be exhibited in a model, bearing but a small proportion to the'■of the original. This is of little moment to the engineer or architect, but to others, unaccustomed to estl , j nSfrom a scale, Class 7 does not appear so imposing as the preceding Classes, although in reality it con ^practical representations of the most mighty works of construction undertaken by any nation in recent tunR. E.