1868.] Gilbert's Patent Iron Ceiling. 61 of the Committee of Science and Arts of the Franklin Institute of Pennsylvania : John McArthur, Jr.; John Stewart; Samuel Sloan ; James H. Windrim ; John Fraser ; George W. Hewitt ; Frank Furness ; J. C. Sidney, Isaac H. Hobbs & Son ; George Summers ; S. D. But- ton, and Richard B. Osborne, Ciil Engineer. J. P. Stidham & Co., Iron Workers, Philadelphia, say : " A No. 18 section of Gilbert's iron-arched ceiling sus- tained, two months, over six tons, dead weight, on the arch itself— all that could be piled on the space, viz., six feet by twenty-eight inches. It was tested in the presence of John C. Trautwine, Esq., civil engineer, and was witnessed by a number of our leading business men." Edward W. Clark, Architect, of Wash- ington, D. C, writes : " I am aston- ished at the rigidity of Gilbert's corru- gated ceiling." N. S. Bouton & Co., of Union Foundry Works, Chicago, Illinois, found that two sections of No. 16 iron arches, six feet long, and constructed as in the building, sustained upwards of nine tons weight which was placed upon it. The result was perfectly satisfactory, and an order given to put the " ceiling " in the new " Tribune Buildings." A ceiling (or floor) constructed of wrought-iron beams and iron-arched plates corrugated, and resting in socket- bearers, will sustain at least two thou- sand pounds to the square foot without any deflection. These ceilings can be put on buildings flat or level, if desired. From the Philadelphia Press, June 15, 1868. King & Baird have published a pam- phlet entitled " Fire-proof Construc- tion," which, in a small space, covers a wide field of utility. Property is liter- ally annihilated, in many instances, to a vast extent, by the devouring element, and, even if there be no loss of life, the interests of the many classes are thereby greatly damaged. A factory or a store may be burned down without injury to life or limb, but the capitalist suffers in his property, losing the profits which would have accrued from the fair em- ployment of his money, and at " one fell swoop " his employes are thrown out of work. The factory may easily be re- built, though this must take time, but it often becomes extremely difficult to re- engage the workmen who are familiar with all the processes. Various plans for rendering buildings almost, if not wholly, fire-proof, have been suggested and tested, with more or less success. The great thing required is to prevent fire, which naturally ascends, from spreading from one story to another. If this could be done, a fire, at the worst, would devastate only the floor upon which its ravages began. The pamphlet before us shows very plainly by plans, sections, and descriptions, how this can be done, and done cheaply. It is by using corrugated iron ceilings, in which strength and rigidity are united to cre- ate the impossibility of a floor being affected by any fire. The plan has been referred to, and most favorably recom- mended, by the Committee of Science and Art of the Franklin Institute, in this city. On a practical question the opinions of practical men must have weight. We give credence, therefore, to such men as J. Vaughan Merrick, Thomas S. Stewart, and Edwin F. Du- rang, (the Franklin Institute Commit- tee,) who report that arched ceilings made of corrugated sheet-iron, fixed to iron beams, with a layer of cement or concrete between floor or arch, can sus- tain a vast weight, and are wholly im- pervious to heat or moisture. The weight of the floor is greatly reduced, the weight upon the walls is thereby di- minished, time is saved, and the cost so much curtailed that the expense need not be greater than that of brick arches on iron beams. The conclusions arrived at by this Committee are " fully en-
