stone was as hopeless, apparently, as its modern derivative, the steel-trussed bridge, until the Greeks, with unerring instinct of art, converted it by perfectly rational processes into that ideal expression of beauty which is known as the Doric order. This Doric order is a structure which depends less upon subsidiary decoration than upon proportion for its unparalleled success as a work of art. The Parthenon would still be lovely without the sculptures of its friezes, metopes, and pediments. Its columns, reduced to dimensions which encumber them with no useless brute mass of material, were so treated with entasis, capital, and fluting as to express exactly members in vertical compression; its lintels were so subdivided as to draw attention to, and to illustrate, all their functions in the structural scheme. They contained no features of caprice or fancy. Now the essential qualities of the steel-girder bridge differ from those of the post and lintel of the Greeks because, in the former, the structure of the lintels permits of a wider spacing of the posts, and the posts have assumed the dual function of piers for vertical support and of buttresses to withstand the horizontal pressures of the stream in which they are built ; the lintels, in their turn, have lost their quality as compact, solid, homogeneous masses, have been resolved into distinct elements, and have become a complicated and highly artificial openwork contrivance of light steel members, which in their dimensions and articulations have been so combined in tension and compression as to produce a structure capable of sustaining without change of form not only its own weight between bearing points far apart, but that of moving trains, and of bearing without detriment vibrations and wind-pressures, and the expansion and contraction of its material by changes of temperature.

These compound lintels or trusses are in themselves triumphs of mind over matter. At this moment they express a stage of evolution which has been in process for a century, and which doubtless will continue to develop in directions impossible to anticipate. They are structures not dedicated to the immortal gods, like the post and lintel in the Greek temples, the decorative character of which was largely inspired by religious emotions, but devised to meet secular and practical conditions of an exceedingly unpoetic and unimaginative character. The mind of the architect appreciates the fine economy of these sensitive and complicated organisms, but it also recognizes that they are still in active process of development; that they are on trial, and will not reach final results until they shall have assumed those conditions of grace and beauty which are essential to completion. It is evident enough that all the features of perfection in animals have been very gradually evolved, by survival of the fittest and by adaptation to use, from the awkward and monstrous shapes of the antediluvian period; that geological erosion and drift have clothed the naked rocks with beauty; and that the  whole  vegetable  creation  has  been improved by art.   Nature  herself is not  contented  with inelastic dogmas.  In  like  manner,  the locomotive, the steam-engine,   the   modern   war-ship,   have  all   become   objects   of   awful