Independeat Water-Heaters usually consist of a suitable jacket made of heavy sheet-iron, forming a combnstion-chamnber, in which is placed a coil of 1+-in. pipe about 14 ft. long. These parts are properly mounted upon a base carrying the grate, with tire-pot and ash-pit, forming a heater of well-known construction. The coil referred to is connected up as a part of a hot-water circulating system. The heat of the combustion-chamber is conducted through• the metal of the coil to the water, by which it is distributed through the circulating While this heater has rendered service for years in car-heating„ it nevertheless has been ft litml that in train-wrecks it is liable to set the cars 011 fire. To overcome this objection several heaters have been designed in which the fire is so inclosed that there is but. little danger of live coals being scattered in case of a wreck. In an improved heater of this type the outside shell is made of 18-in. wrought-iron tubing,. and is over + in. thick. Within this is the cast iron lining, which is separated from the shell by a thickness of asbestos fire-felt, Within this lining is placed a closely wound coil of 1+-in. pipe 26 ft. long. Between the coil and the lining is an annular-shaped '2 in. thick, through which the hot gases from the fire pass to the smoke-pipe on all sides of the coil. The closely wound coil is filled with coal. the fire burning only at the base of the A perforated malleable-iron head is bolted into the upper end of the shell, through which smoke passes before reaching the stove-pipe. in this head a sliding door covers the opening through which coal is fed to the ulterior of the coil. In case the heater should be upset in an accident, the fire can not escape at either end of the Veain-Couplers.—ln continuous heating one of the most difficult problems has been to secure a connection which would couple the ends of the train-pipes together, and so make a practically continuous steam-pipe leading from the locomotive under all the ears. IZubber
hose has now been generally adopted as a means for taking up the motion between cars. and to the end of such hose is attached the steata-cmqder proper. This coupler must eouple uncouple antomatieally. be durable. be exactly alike in half, and the interehange ability must not, bo nirCet011 by wear. 2.11111y typos have hem' brought out, among McElroy, Martin. Gold, Gibbs, and Emerson, embodying some of the above-mentioned desir able features. but the tendency for two years past appears deeilledly to ward what is known as the Sewall pattern. many railroads in the States anti C?111:111t1 having re cently adopted it for steam-heated trains. The Sewall is a port. Om( ting•-fnee, anti instil:1Iva steam-milder. The cuts herewith show its simplicity of c•unstruetiou. The passage for steam is straight and mioh-d met ed by st rain eN, springs. diaphragms, gasket-retainers. or acute angles. All its metallic parts my made of malleable iron or steel. On the crawler-head are laced at tooth end space in proper (shown in arcompHnylug Nit, Fig. 5), to serve the doubletinrpose of guide for the interloelculg when being coupled, and also to retain the coup1er-heads in proper relation while uncoupling. The locking features are constructed upon carefully calculated epieyeloidai curves. thereby drawing the gaskets together in a direct line after contact. The center line of pressure exactly coincides with the center line through the locking devices, and hence gravity tightens the gasket faces. That the coupler is automatic in uncoupling is due to the curvature of the hose-nipple, the center line of draft being brought above the center line of pressure as soon as hose begins to approach a horizontal position. The gaskets are com posed of peculiarly treated rubber and have sufficient elasticity as well as strength to form a perfect and durable steam-joint.
Carriage Drill: see Drills, Rock.