with the hot sheets evaporates and becomes steam, which is then used in
the cylinders to force the pistons back and forth.

6. Q. About what quantity of water should be evaporated in a locomotive
boiler to the pound of coal?

A. From five to seven pounds of water. For example, one gallon of water
weighs eight and one-third pounds, therefore 100 pounds of coal should
evaporate from sixty to eighty-four gallons of water.

7. Q. What is steam, and how is it generated?

A. Steam is water in the condition of a vapor and is generated by
heating the water above the boiling point.

8. Q. What is the purpose of the water gauge glass and gauge cocks?

A. To indicate the level of water in the boiler.

9. Q. What would indicate to you that the boiler connections of water
gauge glasses were becoming clogged?

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