240

GAS-HOLDERS.

quantity of gas contained, the more correct term “ Gas-holders ” is generally applied tothem.

The simplest and most general kind of gas-holder consists of a sheet-iron vessel, open atthe bottom, and inverted into a tank, having perfect freedom to rise and fall, and guided byupright rods fixed at several points in the circumference. The diameters and numbers ofthe vessels will vary according to the magnitude of the works to which they are attached,and the space to be occupied by them. If the works are situated in a town where groundis too valuable to allow an increased extent, double gas-holders that slide into each other,called “ Telescopic Gas-holders,” are used.

Plate XXIV. represents the section of a single gas-holder empty, capable of containing150,000 cubic feet, the diameter being eighty-seven feet six inches, and the height twenty-fivefeet. The sides AA are made of No. 16 iron-plate (Birmingham wire-gauge), weighing 2£pounds to the square foot, riveted together; the top, B, of plate weighing about three poundsto the square foot, or No. 14 gauge.

Fig. 81.

Stone

Plan

CC, etc., are rings of three-inch T-iron, placed five feet asunder, and riveted strongly tothe sides; the rivets ought not to be more than three inches apart. The top and sides aresecured together by three-inch angle-iron, as shown in the woodcut, Pig. 81.

Rings of bar-iron, d d, about half an inch thick and three inches deep, are fastened to the