Of the best Pennsylvania cold-blast charcoal iron, three-eighths inch thick, or of best homogeneous cast-steel, five-sixteenths inch thick; all horizontal seams and junction of waist and fire-box double-riveted. Boiler well and thoroughly stayed in all its parts, provided with cleaning holes, etc. Extra welt-pieces riveted to inside of side-sheets, providing double thickness of metal for studs of expansion braces. Iron sheets three-eighths inch thick riveted with three-fourths inch rivets, placed two inches from centre to centre. Steel sheets five-sixteenths inch thick riveted with five-eighths inch rivets, placed one and seven-eighths inches from centre to centre. WAIST made straight, with two domes, steam being taken from the forward dome; or with wagon-top and one dome. FLUES of iron, lap-welded, with copper ferrules on fire-box ends; or of seamless drawn copper or brass. FIRE-BOX of best homogeneous cast-steel; side- and back-sheets five-sixteenths inch thick; crown-sheet three-eighths inch thick; flue-sheet one-half inch thick. Water space three inches sides and back, four inches front. Stay bolts seven-eighths inch diameter, screwed and riveted to sheets, and not over four and one-half inches from centre to centre. Crown bars made of two pieces of wrought-iron four and one-half inches by five-eighths inch, set one and one-half inches above crown, bearing on side-sheets, placed not over four and one-half inches from centre to centre, and secured by bolts fitted to taper hole in crown-sheet, with head on under side of bolt, and nut on top bearing on crown bars. Crown stayed by braces to dome and outside shell of boiler. Fire-door opening formed by flanging and riveting together the inner and outer sheets. Blow-off cock in back or side of furnace operated from the footboard. GRATES of cast-iron, plain or rocking, for wood and soft coal; and of water tubes, for hard coal. ASH-PAN, with double dampers, operated from the footboard, for wood and soft coal; and with hopper with slide in bottom, for hard coal. SMOKE-STACK of approved pattern suitable for the fuel. CYLINDERS. Placed horizontally; each cylinder cast in one piece with half-saddle; right and left hand cylinders reversible and interchangeable; accurately planed, fitted and bolted together in the most approved manner. Oil valves to cylinders placed in cab and connected to steam-chests by pipes running under jacket. Pipes proved to two hundred pounds pressure. PISTONS. Heads and followers of cast-iron, fitted with two brass rings babbited. Piston-rods of cold-rolled iron, fitted and keyed to pistons and crossheads. GUIDES. Of steel, or iron case-hardened, fitted to guide-yoke extending across, or secured to boiler and frames. VALVE MOTION.