4

THE INDUSTRY OF ALL NATIONS

[From p. 1.]

phitheatre. The plan was recommendedby its economy, the parties offering to putup the whole building for the sum of twohundred thousand dollars. The tower inthe centre was to serve the double pur-pose of a support for the hanging roofof sheet-iron suspended from it by rods ina catenary curve, and also as a grand ob-servatory. For this end it was to be 300feet high, and provide<[ with a mechanismfor hoisting observers to the top by steampower. The height of the exterior wallis about 60 feet. The proprietors, whoare largely concerned in the erection ofcast-iron houses, expressed a convictionthat the whole structure would be worthvery considerably nfore when dissected,for ordinary purposes, than in its presentform, owing to the economy obtained inreproducing so large a number of identicalparts from the same patterns.

The late A. J. Downing- also presentedfor the consideration of the Associationa plan of great novelty and bold concep-tion. We are indebted to the kindnessof Calveiit Vatjx, Esq., of Newburgh,for drawings of the exterior and interiorviews, and the ground plan of this design,and with them we conclude the fourthpage of this number.

The ground plan is a circle intendedto occupy the whole of Reservoir Square,and to be surmounted by a colossaldome, built of wood and canvas, with supporting col-umns of iron. The dome was proposed to be construct-ed with thin curved ribs, placed at short distances,secured with angle iron, and notched into circularties made of several firmly bolted thicknesses of two-inch plank. The stability of the dome depends uponthe ties, which do away with the difficulty of thrust,and leave the weight only of the materials to be sup-ported. The combined strength and lightness of thismode of construction is seen in an eggshell, whosodouble dome of lime is furnished with an uninterruptedtie in the interior by its tough membranous lining.

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The canvas, lining the interior, is designed to be ofpearl-gray color at the springing line, gradually deep-ening into an intense blue at the crown. The ex-ternal ribs, being covered with tin and glass tiles,would produce an effect similar to that of silvering.As this dome would require no centering, and but littlescaffolding, its construction would be both easy andeconomical. The general aim has been to make theinterior light and airy, and to give unity of characterto the design, by avoiding smallness of parts, and ar-ranging in such a manner that it may be conspicuousat a distance and adapted to its position.

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ELEVATION.

GROUND PLAN.