Nature (in the sense of material universe) not improvable by art, [i. 350]; its relation to architecture, [i. 351].
Niches, use of, in Northern Gothic, [i. 278]; in Venetian, [ii. 240]; in French and Veronese, [ii. 227].
Norman hatchet-work, [i. 297]; zigzag, [i. 339].
Novelty, its necessity to the human mind, [ii. 176].
O
Oak-tree, how represented in symbolical art, [iii. 185].
Obedience, how symbolized, [ii. 334].
Oligarchical government, its effect on the Venetians, [i. 5].
Olive-tree, neglect of, by artists, [iii. 175]; general expression of, [iii. 176], [177]; representations of, in mosaic, [iii. 178].
Order, uses and disadvantages of, [ii. 172].