openings, through which the gases pass, the exhaust steam beingdischarged from the lower part of the cone.
To prevent radiation, the boiler is covered over with pine wood,termed cleading, over which, is placed a covering of planishedRussian sheet iron, having brass bands highly polished where theplates meet these bands; they are sometimes beaded or moulded,American engineers priding themselves on the high finish they givetheir engines.
The steam pipe, placed inside of the boiler, is sometimes per-forated as in British practice, the openings in some being a triplerow of slots, each 3^ inches long and % and wide at the fire-box and smoke-box ends respectively. With this arrangement theregulator is placed in the smoke box, and can be more easilyinspected than when inside of the boiler. In other arrangementsthe regulating valve is placed in the steam dorne, an elbow branchpiece being bolted to the side of the dome, taking the steam pipepassing along to the branch piece of the front tube plate; the steampipe in such instances must be made of sufficient strength to preventcollapse.
Two safety valves are generally fitted, placed on the top of thesteam dome; while in others a separate casting is used; this is pre-ferable, as with the former arrangement there is a greater tendencyto priming when the steam is blowing off; lever and spring balancesare generally used, as in British practice, for resisting the steampressure on the valve, and they are arranged so as to be reached byhand, as all safety valves should be; but unless experienced andcareful men are employed as drivers and firemen safety valves of thelever kind may be tampered with in whatever position they may beplaced on the boiler. The safety valves are generally fitted at thetop of the safety-valve ehest, while others are arranged on the cast-iron cover, forming the top of the steam ehest, and are carried suffi-ciently high overhead, thus dispensing with steam funnels for carryingoff the steam. The covering for the steam dome is of polished brassvery elaborate in design; in some there is merely a bottom piece,with a recess at top of moulding for letting in the wood lagging,and which is secured at the top with a strap, the whole beingcovered with Russian iron highly planished.
Glass water gauges are not generally adopted in American loco-motive engines; sometimes gauges on the float principle are usedfor indicating the height of water in the boiler, while others have