2. When adding coal to the boiler, open the smoke-pipe damper (inside the smoke pipe) and close the cold-air check damper. This will make a draft through the feed doorway inward and prevent the escape of dust or gas into the cellar when the feed door is open to take fuel. Put these parts back to their regular places after feeding. 3. When it can be done, in feeding a large amount of coal (as for night) leave a part of the fire or flame exposed, so that the gases may be burned as they arise. 4. When a regulator is not used, learn to use the dampers correctly and according to the force of the chimney draft. Learn to use cold-air check damper. Often, when closing, the ash-pit draft damper does not check the fire enough; opening the cold-air check damper will check it about right. Increasing or lessening the pressure of a steam boiler must be done by changing the weight on the regulator bar. 5. Carry a deep fire or a high fire; let the live coals come up to the feed door--even in mild weather when from 4 to 6 inches of ashes stand on the grate. [Illustration: FIG. 57_a_.--Indicates the general condition of the furnace fire during very cold weather. The fuel should fill the fire-pot to _C_. The ashes should not be allowed to accumulate beyond _B_, on the grate. There should be no more ashes than appear at _H_, in the ashpit.] 6. In severe weather give the heater the most careful attention the last thing at night. 7. Do not overshake or poke the fire in mild weather; once in a while shake enough to give place for a little more fuel. 8. Do not let ashes bank up under the grate in ash-pit. Grate bars are very hardy, but it is possible to warp them with carelessness. Taking up the ashes once a day is the best rule, even if but little has fallen into the pit. 9. Keep the boiler surfaces and flues clean; a crust of soot 1/4 inch in thickness causes the boiler to require half as much more fuel than when the surfaces are clean. 10. If convenient, have a water hose to spray the ashes when cleaning out the pit. 11. Attend the boiler from two to four times per day. In mild weather, running with a checked fire, morning and night is usually often enough. In severe weather, once in early morning, again at mid-day, again at five or six o’clock and finally thorough attention at from nine to eleven o’clock in the evening. 12. If, through burning poor coal, the fire pot gets full of ashes, or slate and clinkers massed together, the quickest way to get a good active fire is to dump the grate and then build a new fire--from the kindling up. 13. If a _hard clinker_ lodges between the grate bars, do not force the shaking, but first dislodge the mass with a poker or slicing bar. Then the grate will operate without damage.