CHAPTER XLIII.

=MARINE BOILERS.=

=Plates for Marine Boilers= 452 Iron 452 Steel 452 Strength of 452 =Boiler Stays= 452 Methods of securing 452 =Boiler Tubes= 452 Methods of securing 452 Causes of leaks 452 Repairing leaks 452 =The Up-take= 453 =The Receiver= 453 =The Fittings and their Uses= 453, 454 Valves 453, 454 Gauges 453, 454 Cocks 454 =Important Features and Facts= 454, 455 Boiler scale 454 The salinometer 454 Priming, the prevention of 454 Supplemental parts 454, 455 The superheater 454 The draught 455 Wasting of plates 455 Fuel, the quantity of 455 =To Relieve the Boiler in Case of Accident= 455 =Steel Marine Boiler= 456 =The "Martin" Boiler= 456 =Testing and Examining Boilers= 456 to 459 Hydraulic tests 456 Related to stays 456, 457 On new and old boilers 456, 457 Internal examinations 458 Preparation for 458 Safety valves 458 Bottom of the boiler 458 Bottom and sides of the furnace 458 Boxes and stays 458 Use of chipping hammer 458 Pit holes in the bottom of a furnace 458 Drilling through the plates 458 Flanges of furnaces 458 Deposits on the necks of stays 458 Man-hole door 458 Superheater 459 Proportions for grate surface 459 Outside examination 458 Cement beds for boilers 458 Proportions for circular tubular boilers 459