condenser and the air-pump, opening towards the latter. Forcing pumps (F. pompes foulantes; G. Druckpumpen; S. bómbas de forzár).

Fork (F. fourchette; G. Gabel; S. horquilla).

Fork-head (F. tête fourche; G. Kopf gabelförmig; S. remáte ahorquilládo), the double head of a rod which divides in order to form a connection by means of a pin. Foundation or base plate (F. plaque de fondation; G. Fundamentsplatte; S. peána), see Sole plate. Fox key (F. contre-clavette; G. Gegenkeil; S. contralláve), is a key with a thin wedge of steel driven into the end, to prevent its working back. Frame of the engine (F. châssis; G. Maschinengestell; S. armazón). Frames of a vessel (F. membres d'un vaisseau; G. Inhölzer des Schiffes; S. miembros de un búque). Friction (F. frottement; G. Reibung; S. fricción).

Fuel (F. combustible; G. Brennmaterial; S. combustible). Fulcrum (F. point d'appui; G. Stützpunkt; S. púnto de apoyo). Furnace (F. fourneau; G. Ofen; S. fornálla).

Fusible plugs (F. rondelles fusibles;

G. schmelzbarer Stöpsel; S. tapóns fusíbles), are sometimes fitted in boilers, being expected to melt by the high temperature of the confined steam, and thus allow it to escape in case of its attaining a dangerous pressure from the safety-valve not acting.

Gasket (F. garniture de chanvre; G. Hanfliederung; S. cája pára empaquetár), is the hemp packing, formed of soft cord plaited, which is used for making steam-tight joints.

Gauge cocks (F. robinets d'épreuve; G. Probirhähne; S. lláves de pruéba), of brass attached to the front of the boiler, for indicating the level of the water.

Gauge, steam or mercurial (F. manomètre; G. Dampfmesser; S. manómetro), is a siphon tube half filled with mercury, usually employed for showing the pressure of low steam. When a marine boiler uses steam

of high tension, a spiral spring is employed.

Gb (F. contre-clavette; G. Gegenkeil; S. pérro), is the fixed iron wedge used, in conjunction with the cutter or driving-wedge (clavette), for tightening the straps and brasses of the different bearings. Gland (F. boîte à étoupes; G. Stopfbüsche; S. collarín de la bárra del émbolo), is the cupped collar, lined with brass, which encircles the piston and air-pump rod, &c., where it passes through the cover, being for the purpose of holding oil or tallow for lubricating, and for compressing the packing of the stuffingbox upon which it is screwed down. Glass water gauges (F. indicateurs du niveau de l'eau; G. Wasserstandsmesser; S. hidrómetros), attached to the fronts of the boilers for showing the level of the water. Governor (F. régulateur; G. Regulator; S. reguladór), in screw engines, is an apparatus by which the steam is shut off from the cylinders, when the speed of the engine becomes too great, by the divergence of two balls from the centrifugal force, according as their velocity is increased.

Grease cock (F. robinet graisseur; G. Oelbüchse; S. cópas de lubricadór), on the cylinder cover, for lubricating the piston with melted tallow, without permitting the escape of steam or the entrance of air.

Groove (F. creux; G. Einschnitt; S. ranúra).

Guards (F. gardes; G. Eingerichte; S. guárdas de tuércas), for the bolts of an engine, are light frames of brass or iron, into which the nuts of the bolts fit, to prevent their working loose by unscrewing. Gudgeon (F. goujon; G. Zapfen; S. pernéte), is any short pin or shaft used as a bearing for a moving portion of the machinery.

Guides (F. glissières; G. Parallelführung; S. guías), are smooth surfaces between which the head of a piston-rod, &c., slides, to preserve its parallelism; the sliding block attached to the cross-head being called the Guide block.

Gun metal (F. bronze a canon; G.

Kanonenmetall; S. brónce), an alloy

of brass very generally employed in engine work. It is formed by melting together 1 lb. of tin, 1 lb. zinc, and 8 lbs. copper. Hall's condensers, a method of surface condensation in which the steam is condensed by passing through a large number of small tubes immersed in cold water. Hammers (F. marteaux; G. Hämmer; S. martillos), of three sizes, the largest being called sledge hammer; the next, flogging hammer; and the smallest hand hammer. Handle (F. manche; G. Heft; S. mángo).

Hand pump (F. pompe à bras; G. Handpumpe; S. bómba de máno), is fitted in the engine-room for filling and feeding the boilers by hand, for washing the decks, extinguishing fire, &c. It is always made capable of being attached to the engines when they are working.

Heat (F. chaleur; G. Wärme; S. calór) heating power (F. puissance calorifique; G. Heizkraft; S. fuérza calorífica).

Helm (F. timon; G. Helm; S. timón): helmsman (F. timonier; G. Rudergänger; S. timonél).

Hemp (F. chanvre; G. Hanf; S. estópa).

High-pressure, or more correctly, non-condensing engines (F. machines à haute pression; G. HochdruckDampfmaschine; S. máquinas de álta presión), are those which work simply by the excess of the pressure of the steam above that of the atmosphere. Condensing engines, although sometimes using "high-pressure" steam, are never called high-pressure engines. High-pressure steam (F. vapeur à haute pression; G. HochdruckDampf; S. vapór de álta presión), is a vague expression denoting steam of a tension above 15 or 20 lbs. pressure above the atmosphere. Hinges (F. fiches; G. Scharnierbänder; S. gónces).

Holding-down bolts (F. boulons de carène; G. Kielbolzen; S. pérnos de asegurár la máquina), are the strong screw-bolts employed to fasten the foundation plate of the engines to the ship's bottom. Horse-power (F. force de cheval; G.

Pferdekraft; S. cabállo de vapor), is assumed equal to 33,000 lbs. raised one foot high in one minute. Hot-water pump (F. pompe d'alimentation; G. Warmwasser-Pumpe; S. bómba de água caliente).

Hot-well (F. réservoir d'eau chaude; G. Heisswasserbehälter; S. déposito de água caliénte), is the reservoir for the water pumped out of the condenser by the air-pump. Hugging is the expression used when one vessel is running so close in the wake of another as to be influenced by the current of dead-water following her, in which case the two may continue to keep close together, although the vessel running behind may be, perhaps, a mile an hour slower than the other.

Hull or shell of a boat (F. coque d'un bateau; G. Rumpf eines Schiffes; S. cásco de un búque). Hydraulic ram (F. bélier hydraulique; G. hydraulischer Stösser; S. ariéte hidraúlico).

Incrustation or scale (F. sédiment; G. Niederschlag; S. sediménto), is the hard coating of salt, lime, and other mineral substances which collect on the inner surface of the plates of a boiler which is not regularly and sufficiently "blown off." Index of a spring balance (F. indice à la balance à ressort; G. Anzeiger von die Federwage am Sicherheitsventil; S. índice á péso de muélle). Indicator (F. indicateur; G. Weiser; S. indicadór), is the little instrument employed for ascertaining the real power, as well as the state of efficiency of the internal parts, of a steam engine, by indicating the actual pressure in the cylinder during each stroke, and the time and manner in which the steam is admitted and shut out by the valves. Injection (F. injection; G. Einlass; S. inyección), is the process of admitting a jet of cold water from the sea into the condenser to condense the steam as rapidly as pos

sible.

Inside bearings of paddle shaft (upon a bracket bolted to the ship's side), are employed when the wheels are "overhung."

Intermediate shaft (F. arbre inter

valve being required. It also affords great facilities for stopping and reversing the engines. Linseed oil (F. huile de lin; G. Leinöl; S. aceíte de lináza). Log, engine-room (F. loc; G. Logg; S. diário de máquina), a tabulated summary of the performance of the engines and boilers, and of the consumption of coals, tallow, oil, and other engineers' stores. Lubricators (F. godets à huile; G. Oelkännchen; S. lubricadóres), are the larger description of oil-cups for holding oil and distributing it to the working parts of the engines.

Machinery (F. mécanisme; G. Mechanismus; S. maquinària). Main centre (F. goujon central; G. Bolzen; S. céntro de los balancínes), in side-lever engines, is the strong shaft upon which the side levers

vibrate.

contact.

Mortise (F. mortaise; G. Zapfenloch; S. escopleadúra).

Mortising (F. assemblage à mortaise; G. Verzapfung; S. escopleádo). Mud-hole (F. orifice de nettoiement; G. Schlammloch; S. regístro de limpiéza en las caldéras), a space fitted with steam and water-tight doors, through which the deposit may be removed from the boilers. Muntz's metal (F. métal de Muntz; G. Muntz-metall; S. metál de Muntz), used for bearings, &c., is formed of 2 parts of zinc, 3 parts

copper.

Nave of a wheel (F. moyeu; G. Radnabe; S. centro),

Neck of a shaft (F. coussinet d'un arbre; G. Schaft-Lager; S. cuéllo de un ége), is the journal or bearing on which it turns and is supported. Non-condensing or high-pressure engine (F. machine à haute pression; G. Dampfmaschine mit Hochdruck; S. máquina de álta presión), is that in which the principle of condensation is not applied, the motive power being due solely to the excess of the pressure of the steam above that of the atmosphere.

Notch (F. encoche; G. Anschnitt; S. mortája).

Nut (F. écrou; G. Mutter; S. tuérca).

Oil-cups or lubricators (F. boîtes à huile; G. Oelkännchen; S. lubricadóres), are fitted to the several bearings and rubbing surfaces of the engine, for the purpose of lubricating them to diminish friction. Oscillating engines (F. machines oscillants; G. oscillirende Dampfmaschinen; S. máquinas oscilatórias), are those in which the cylinders oscillate upon hollow axes or trunnions, through which the steam enters the valve-casing. By this arrangement, the parallel motion and connecting-rod are dispensed with, the head of the piston-rod being attached directly to the crankpin.

Outside bearings to paddle-shaft, when the shaft runs through to a bearing on the spring beams. Overhung paddle-wheels (F. roues à palettes en surplomb; G. Schau

felrad überhängig; S. ruédas de un vapór suspensas), when the shaft does not run through to a bearing on the spring beams, but is supported by a bracket from the ship's side.

66

Packing for the piston, slide-valves, &c. (F. garniture de piston; G. Dampfkolbenliederung; S. empáque del émbolo), is employed to render them steam-tight, and is formed sometimes of rings of iron or other metal pressed outwards by springs (when it is called metallic packing); sometimes by hemp confined by a 'junk ring," and compressed by screws (called hemp packing); and sometimes by rings of vulcanized india rubber and other elastic material. Paddle-wheels (F. roues à palettes; G. Schaufelrad; S. ruédas de un vapór). Paddle-boxes (F. tambours des aubes; G. Radkasten; S. tambores). Paddle-boards or float-boards (F. aubes; G. Schaufeln; S. palétas). Paddle-arms (F. rayons des roues; G. Radspeichen; S. palétas). Parallel motion (F. parallélogramme;

G. Parallelbewegung; S. movimiento paralelogramo), is the name given to the combination of jointed rods usually employed in side-lever engines, and others, for preserving the parallelism of the piston-rod. Pedestal or plummer block (F. palier; G. Lager; S. chumacéra), is the support for a shaft in motion, holding the brasses on which it turns. Pet cock or test cock (F. robinet d'essai; G. Probirhahn; S. lláve de hechar fuéra el água del cilíndro), is the name given to a little cock sometimes fitted at the top and bottom of the cylinder, to allow the escape of water from above and below the piston, independently of the escape-valves fitted for that purpose. They are kept open until the engines are fairly under weigh, and are then shut.

Pin (F. boulon; G. Bolzen; S. pernéte).

Pinion (F. pignon; G. Getriebe; S. piñón).

Pipe (F. tuyau; G. Rohr; S. túbo). Piston (F. piston; G. Kolben; S. émbolo).

Pitch circles (F. cercles primitifs; G. Theilkreise; S. círculos primitívos), the circles of contact of two or more toothed wheels working in combination.

Pitch of a screw (F. pas de la vis; G. Ganghöhe; S. avance de un tornillo), the distance between the threads, or the distance which the screw advances during each revolution when working in a solid. Pitch of a wheel (F. pas de l'engrenage; G. Theilung; S. ábra de diéntes).

Pitching of a vessel (F. plongement; G. Senkung; S. cabezáda de un búque).

Plank (F. planche; G. Planke; S. tablón).

Plates (F. tóles; G. Schwarzbleche ; S. planchas).

Plug (F. tampon; G. Stöpsel; S. tapón).

Plummer block, see Pedestal.
Plunger (F. plongeur; G. Pumpen-

kolben; S. émbolo sin válvulas de
una bomba), a solid piston with-
out valves, used in the feed and
bilge pumps, &c.

Ports of the cylinder (F. lumières de cylindre; G. Dampfwege; S. pórtas del cilíndro), the short steam passage leading from the top and bottom of the cylinder to the slidevalve casing.

Priming or foaming of the boilers (F. jet de mélange d'eau et de vapeur; G. Auslassen von Dampf und Wasser; S. fomentár de las caldéras), implies that the water boils over into the steam-pipes which lead to the engines, and is caused by the water being dirty, or from a deficiency of steam-room in the top of the boilers.

Priming valves, see Escape-valves. Pulley (F. poulie; G. Kloben; S. poléa).

Radius of curvature (F. rayon de

courbe; G. Krümmungshalbmesser; S. rádio de una cúrva). Radius rods or bars (F. bras de rappel; G. Gegenlenker; S. rádios del paralelógramo), the guiding rods in a parallel motion jointed to the connecting links to counteract the vibratory motion communicated by the side levers.