A. The up and down movement of the water in the glass would become slow and inactive, or it would not register correctly with the gauge cocks.
10. Q. At what temperature does water boil?
A. At atmospheric pressure, which is 14.7 pounds at sea level, water boils at 212 degrees Fahrenheit; the temperature, however, increases as the pressure under which the water is boiled increases. At 200 pounds boiler pressure the temperature would be 388 degrees Fahrenheit.
11. Q. What is carbon?
A. Carbon forms the greatest part of all kinds of coal; the higher the per cent. of carbon, the higher the grade of coal.
12. Q. What is the composition of bituminous coal?
A. It is composed of carbon about 75 per cent. and many gaseous substances, as is shown by its burning with a large flame and much smoke. Anthracite, on the contrary, is nearly pure carbon and burns with a small flame.
13. Q. What is combustion?
A. Combustion or burning is a chemical process, it is the action of fire on inflammable substances and is the union of the oxygen in the air with the carbon in the fuel; this is called rapid combustion. Slow combustion is the decaying of wood or iron by the elements.
14. Q. Is air necessary for combustion?