Every period of English Gothic architecture has certain forms appearing in the general composition and details which help to fix the period to which they belong. In the Norman the _square_ and the _circle_, the right angle and the semicircle, are the prevailing figures suggestive of strength and severity so evident in the impressive naves of Ely, Peterborough, Norwich, Gloucester, Tewkesbury, and the fortress-like cathedral of Durham. Plate III. gives a few details of work of the Norman period. The term _pier_ (Plate III., Fig. 1) defines the pillars or masses of masonry supporting the arches between the nave and aisles of a church. This example (Plate III., Fig. 1), from St. John’s Chapel in the White Tower of London, William the Conqueror’s residence, is circular with a square capital chamfered down to the circular pier, and has a slightly moulded _abacus_ (the crowning moulding of a capital). Plate III., Fig. 2, the _cushion capital_, is the simplest kind of Norman capital. It is cubical, with its square faces rounded down to the shaft. [_Note._--The _shafts_ of all English Gothic columns are cylindrical--_i.e._, without any diminution towards the top, in contrast with Greek and Roman shafts, which are always diminished.] Plate III., Fig. 3, is the capital of a _respond_--a half-column attached to a wall and carrying an arch or part of a roof. Plate III., Fig. 4, the _corbel-table_, or cornice underneath the eaves of a roof (_corbel_--a bracket). Plate III., Fig. 5, the _base_ of a pier with _spur_ ornaments. Plate III., Fig. 6, fragment of a Norman arch of _four orders_, each order being a separate arch, three of which are enriched with the Norman _chevron_. The _dripstone_ or _hood-moulding_ (d.s.) encloses the arch as in Plate III., Fig. 8, though its original function--to protect the moulding under it from weather--is not needed here, but it is generally introduced to give effective finish to the arch. The capitals in this group are _scallop capitals_. A small portion of a similar capital is shown at the right hand of Plate III., Fig. 3. Plate III., Fig. 7, is a Norman font of the simple bowl form enriched with carved Norman heads connected by Byzantine ornament and surrounded with a _Norman arcade_ of intersecting arches--a feature often introduced in the walls of churches and cathedrals. Plate III., Fig. 8, is a double-recessed window with an arch of three orders. The columns in the positions shown are called _jamb-shafts_ or _nook-shafts_; those on the right are _detached_ and may be removed, leaving the bases and capitals remaining. On the left the shafts are _engaged_--_i.e._, form part of the masonry of the wall. These two varieties are never found together as here, but are thus shown for convenience. The capitals are a variety of the cushion capital. Plate III., Fig. 9, is a _cushion capital_ with the _triquetra_ symbol of the Trinity (Plate I., Fig. 8).