The Adelphi were no less formal in their modes of expression than their predecessors, but their formality was vastly more varied, richer and intensely genial. There was a finesse and a polish about their conceptions that fully accorded with the spirit of the day, a period which someone has aptly termed the "age of the drawing-room." Indeed, they may be regarded as in no small degree responsible for the creation of that spirit. One of the eminently pleasing forms in which their humanised formality found a fresh outlet was in the varied shapes of the rooms frequently introduced into their compositions. Hitherto, although rooms were designed with a due regard for satisfying symmetry in their proportions, they were habitually rectangular in shape. Not content with confining themselves to the monotonous convention of rectangularity, the Brothers Adam made the very shapes of their rooms fulfill a decorative purpose and frequently designed circular, semicircular, octagonal, oval and elliptical apartments or rooms with semi-circular, arc-shaped, tribune or ar-caded ends when they deemed that, by so doing, they could enhance the elegance, vivacity or interest of their creations. At the same time they made the ceilings (Plates 10 and 159) and floors enter into a comprehensive and inter-related scheme of decorative unity that had rarely before been equalled.

To a greater extent, perhaps, than had ever been done previously, they treated the walls of their more important rooms as architectural compositions (Plate 10), distinct and complete in themselves, with a due and ordered disposition of panels (Plate 10), pilasters, capitals, pediments, friezes and cornices. All of these features were usually in low and rather flat projection so as to emphasise the sense of space and prevent them from seeming unduly obtrusive, unless the apartment was so large that it could easily stand a succession of bold projections without their becoming oppressive or destroying the aspect of spacious freedom. The decorative details, both upon these architectural members and upon the panelled or other intervening flat sur-faoes, were refined and delicate in scale and in low relief. Pilasters, pediments and other dominant projections were sometimes fashioned in carved wood, but more frequently were executed in plaster; the low relief wall panels and other ornamental details were almost invariably done in plaster or compo. Never before had the art of the plasterer or of the worker in compo been given so ample an opportunity to display its manifold possibilities and charms.

The panels, or successions of panels, were often covered with a complete and sufficient decorative design of airy arabesques, urns, paterae and other motifs in low relief and the effect of this rich mural adornment was generally further enhanced by the use of a pale-coloured background in order to throw the raised work into sharp contrast. At other times the wall panels exhibited no plaster or compo relief but were painted, upon a solid body colour, with devices similar to those employed in the reliefs just mentioned.

Even with their plainer and less pretentious walls, on which there was no display of architectural features, decorative panels, either in relief or painted, were used to good effect and constituted a valuable item of fixed embellishment. On walls of a still less elaborate type - walls in the Adam mode varied from the utmost exuberance of detail to the opposite extreme of classic austerity - countersunk panels and niohes were introduced, either in conjunction or separately, and were so disposed that the most striking results were obtained from the agreeable alternation of light and shadow, for the Adelphi were masters in the management of this simple but often neglected and misapplied resource, as they also were in their handling of low relief. On the plainest walls, whose surfaces were unbroken by either projections or depressions, the rich and delicate detail of the cornice (Plate 69), along with the decoration of door and window trims, was skillfully manipulated to present an elegant contrast between concentrated ornament and foil. Wooden panelling entered little if at all into the interior decorative schemes of the Brothers Adam for they were too deeply imbued with the ideals they had formed during their travels and researches in classic lands to be much enamoured of this method of wall treatment, notwithstanding the great body of previous English precedent and the materials at their disposal. Instead of wooden panelling, they occasionally employed marble, but their methods of treating plaster were capable of such agreeable variety that there was little need to resort to other means of interior finish. In a great number of cases, - especially with the plainer walls, a chair rail or moulding was carried around the room, thus creating the appearance of a base for the treatment above. In some instances, also, fabrics and wall-paper were used, but painted walls seem to have accorded more nearly with the spirit of Adam interior backgrounds. The system of colouring commonly employed will be more fully discussed in a subsequent section, but it seems advisable at this point to call attention to what an extent the ensemble of Adam interiors was dependent upon the light, delicate and often pale tones of the flat wall surfaces.

Decorative paintings of landscapes (Plate 159) and architectural subjects, in the Italian manner worthily represented in England by Cipriani and others of his fellow-countrymen who had heeded the invitation of the Adelphi, were plentifully used and were set either in countersunk panels or in flush panels surrounded with plaster or compo mouldings in the fashion of a frame. These panels were introduced with great frequency and in various shapes over (Plate 11) doorways, above fire-places and wherever else decorative expediency dictated. Wedgwood plaques (Plate 159), with designs by Flaxman or Lady Templetown, were often made the central features of arabesque panels, and large plaster or Wedgwood medallions, with heads or with classic figures in low relief, frequently occurred either with an accompaniment of flowing arabesques to enrich a large wall or overmantel panel, or else in a severely chaste composition as the sole enrichment of one of the smaller countersunk panels already mentioned. Busts or other pieces of sculpture (Plate 10) were sometimes strikingly used for wall decoration and so placed that the shadow of a niche behind them supplied a most impressive background against which they were silhouetted.