PLATE XVII.

Fig. 1. is a section of a steam vessel with its boiler in two parts; the right part is shewn in a section across it through one fire place F, and its flues N, P; and through the cross flue L of the other fire place, and through the safety valve U, (art. 263;) shewing the dampers O, R, and the passages of the flues to the chimney. Of the left part the fire door end is shewn, with the fire doors D, D, the handles for clearing the clinkers B, B, the doors for cleaning the flues at E, E, E, and the gauge cocks G; also part of the chimney C, the steam pipe S, and a slide valve V, to shut off the steam from the engine. There should be as much space between the boiler and the sides of the vessel, as to admit a person to go round to examine it. The floor under the boiler should be rendered as strong as possible, and the boiler should rest on a plate of iron bedded on a layer of bricks or tiles laid over the floor in cement; in this manner a thin plate of wrought iron extending under the whole, being flexible, and brick a slow conductor of heat, is more secure than a much thicker cast iron plate.

Fig. 2. is a plan, shewing the arrangement of the two fire places F, F, and their flues. The fire door is at D, the fire on the grate F, the clinkers fall at H, and the smoke turns at L and returns along the flue N, rises at O, and goes back along a flue P over N. The boilers should be strengthened by internal frames disposed in triangles, and so as to afford supports for the flues.

Fig. 3. is a longitudinal section through the boiler, and one of the fire places: the same letters refer to the same parts in all the figures, (see art. 239-244 ;) for the fire and flue surface (art. 204;) for the capacity (art. 215-220;) for the area of the chimney (art 278;) for safety valves (art. 259-272;) for the strength of boilers (art. 525;) and for the management of sea water (art. 565.)

Fig. 1. is a section of a steam vessel with its boiler in two parts; the right part is shewn in a section across it through one fire place F, and its flues N, P; and through the cross flue L of the other fire place, and through the safety valve U, (art. 263 ;) shewing the dampers O, R, and the passages of the flues to the chimney. Of the left part the fire door end is shewn, with the fire doors D, D, the handles for clearing the clinkers B, B, the doors for cleaning the flues at E, E, E, and the gauge cocks G; also part of the chimney C, the steam pipe S, and a slide valve V, to shut off the steam from the engine. There should be as much space between the boiler and the sides of the vessel, as to admit a person to go round to examine it. The floor under the boiler should be rendered as strong as possible, and the boiler should rest on a plate of iron bedded on a layer of bricks or tiles laid over the floor in cement; in this manner a thin plate of wrought iron extending under the whole, being flexible, and brick a slow conductor of heat, is more secure than a much thicker cast iron plate.

Fig. 2. is a plan, shewing the arrangement of the two fire places F, F, and their flues. The fire door is at D, the fire on the grate F, the clinkers fall at H, and the smoke turns at L and returns along the flue N, rises at O, and goes back along a flue P over N. The boilers should be strengthened by internal frames disposed in triangles, and so as to afford supports for the flues.

Fig. 3. is a longitudinal section through the boiler, and one of the fire places: the same letters refer to the same parts in all the figures, (see art. 239–244 ;) for the fire and flue surface (art. 204;) for the capacity (art. 215-220;) for the area of the chimney (art 278;) for safety valves (art. 259-272;) for the strength of boilers (art. 525;) and for the management of sea water (art. 565.)