Q. How often should it be blown out?
A. Three or four times a day.
A. How much grate surface do boiler makers allow per horse-power?
A. About two-thirds of a square foot.
Q. What is the steam dome of a boiler used for?
A. For dry steam to collect in.
Q. Of what use is a safety valve on a boiler?
A. To prevent overpressure.
Q. What is your duty with reference to it?