I shall now very briefly point out a few deviations from ancient practice, observable in the interiors of modern buildings. Our lath and plaster panelled and groined ceilings are purely imitative and useless. Ponderous looking beams, through which we might poke our walking sticks could we but reach them, feign to support realities they merely hide. In the place of the ancient cornice, which served to aid in supporting joists and roof beams, we fasten up plaster hollows, rounds, and flats, all specially formed so as to contain as many as possible of stereotyped castings, technically called enrichments; and we appear to consider these plaster forms so many indications of our progress in appropriate decoration; whereas, so far from ornamental plaster work ever having been associated with true architectural progress, it came prominently into use only on the decline of truthful art. When surface decoration came to receive too much attention from the architect, and in consequence the supply of ornament did not keep pace with the demand, the worker in plaster was brought to aid the sculptor and the carver, just as he has again to suit the demand created by commercial art in our times, given place to the moulder, or castor of previously existing ornaments, whose talents we do not confine to moulded or panelled ceilings, but occasionally employ in imitating ancient wainscoting, thereby making it appear that we consider wood panelling to be the mere whim of the carpenter, instead of what it is, a constructive necessity on his part, for he can no more finish the interior of a room with one board than a mason can build a wall with one stone. Therefore, we may term panelling building in wood; and were architects, instead of designing plaster imitation panels, to encourage and instruct carpenters how to emulate their brethren of former times, they would undoubtedly be doing more towards the

advancement of genuine constructive Architecture. Another instance of idle copyism will be found in the form and use of those features called door-capes. In olden times, monograms, mottoes, and other appropriate devices, were carved and placed over doors immediately above the architrave. Now in imitation of, and in the place of those ancient friezes, our architects put up plain boards, which they surmount with Grecian and other cornices, for the purpose, as they say, of making the door-ways have a loftier appearance, and for the like reason they construct empty pediments. Now we should not, I presume, pay much attention to the advice of any architect who would advise us, in order to break the plainness of an interior wall, to hang thereon a number of empty picture frames, and yet what are all those empty pediments we see on the interior, and on the exterior of classical and other buildings, but empty sculpture frames? When placed over doors and windows, as they usually are, on what are called Italian elevations, they serve no useful purpose whatever; not being intended for, they are not constructed so as to serve the place of drip mouldings. These empty pediments are idle features of an idle style, and nothing more; and I believe, had not the long continuance of the practice blinded us to the folly, we should scarcely feel disposed to carry it on now at so much cost.

Before concluding, allow me to express an earnest hope, that these remarks will be taken in good part. They have been made from an honest motive and with a good intention, in the belief that useful and ornamental Architecture cannot result from the eye and the hand alone, but must be the work of reason, acting along with an innate feeling for beautiful form. Our sense of fitness must be satisfied when the mind is employed in designing for useful purposes; not so, however, when engaged in the practice of imitative

Architecture. No constructive fitness comes to disturb the even tenor of the plagiarist's thoughts. He goes on comfortably, copying, arranging, and re-arranging; now and then, it may be, inquiring if there is any likelihood of a new style arising, and conjecturing, whether it will come out of the materials of iron and glass, or be produced by a new arrangement or combination of the leading features of former styles, and so stand forth a purely decorative conglomerate, formed by the uniting of all previously existing remains.

In conclusion, I beg to repeat my belief, that could we only bring ourselves to follow ancient example, allow our requirements to suggest the form of our buildings, or in other words, give greater consideration to " what is convenient as a house," we should sooner arrive at being really correct in architectural design," and out of this regard for truthful form, re-create the only true style.

TRANSACTIONS OF THE ARCHITECTURAL INSTITUTE OF SCOTLAND,

SESSION 1855-56.

No. IV.

ON

WROUGHT AND CAST IRON BEAMS.

BY

THOMAS DAVIES, Esq. F.A.I.S.

[Read at a Meeting of the Institute in Edinburgh, held on 18th February 1856.]

I. WROUGHT IRON BEAMS.

THE material first used in the construction of Beams was doubtless timber, and although it has many properties peculiarly fitting it for this purpose, yet, on account of its flexibility, and the difficulty of getting it of sufficient size and strength for long spans, its tendency to decay, and its destructibility by fire, it is in many cases unsuited for the purpose required.

When the manufacture of cast metal became more general, and the means were obtained of making large castings, the applicability of this material to the formation of beams could not fail to suggest itself. This material has decided advantages in its rigidity, in its capability of being made of almost any required shape and strength, in its non-liability to decay, and in its incombustibility; and consequently, it has come to be very extensively used for the purpose referred to.

There has, however, been a general want of confidence in Beams of this material, arising from different causes. One objection is, that when a beam gives way, it does so without any previous warning. Another objection is, that although we have innumerable experiments on the strength of cast-metal, by which we are enabled to calculate the amount which any particular Beam of this material ought to carry, it does not follow that it will bear that

amount. In a large casting there may be some inequality in the metal used; again, if there is much difference in the thickness of the parts, the cooling of one part before another produces, to some extent, a tendency to fracture, especially if subjected to any sharp concussion; or the casting may be clean and apparently sound, and yet there may be a flaw, of which nothing can be known until it is revealed by a fracture. No doubt, to guard against these defects, we have the system of testing; but this is not always to be depended upon, as it has been considered, that in some cases Beams have been tested so nearly to the limits of their strength, that, though passing the ordeal, they have been permanently injured thereby. This suggests another objection, that though a Beam be in every way sound, yet, if it is occasionally subjected to great strains, it will ultimately be so much weakened, as to break with a load much less than the original breaking weight.

The result of the want of confidence above mentioned has been, that cast-metal beams are generally made much stronger, than, judging from experiment, they require to be, necessitating heavy castings and increase of cost, with the additional drawback of great weight and difficulty of handling.

Malleable iron Beams unite, to some extent, the advantages of both timber and cast-metal. They possess the advantage of timber, inasmuch as they are comparatively light, and therefore easily handled, and when overloaded, they show this by yielding considerably before breaking. They possess the advantage of castmetal in their incombustibility, in their being capable of being conveniently made of any required strength, and even to some considerable extent, in their rigidity; for although malleable iron is comparatively flexible, yet this quality is in a great measure counteracted by the mode of constructing the Beams.

Messrs. Stephenson and Fairbairn, in their investigations and experiments relative to tubular bridges, were the first to call general attention to the use of malleable iron in the construction of Beams. After many experiments on various sections of tubes, they arrived at the rectangular tube, or Box Beam, as the best; and it was a simple step, by dividing it in two by a vertical line, to come to the double flange or Plate Beam, which is the most convenient shape for general use.

Mr. Fairbairn, in his valuable book on cast and wrought iron, shows the superiority, in many respects, of malleable over cast-iron