Fig. 3407.

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Fig. 3406.

Chapter XLIII.—MARINE BOILERS.

Boilers for marine engines are, in England, made of special qualities of plate, the best being termed Yorkshire, and a nearly equal grade, Staffordshire. The plates for the shell, the furnace bottoms and the gusset stays are made of Staffordshire, while the tube plates, furnace tops, and such parts as require to be flanged and are subject to more intense heat, are made of Yorkshire plate, which has more ductility.