142
THE HONGKONG GOVERNMENT GAZETTE, MARCH 11, 1910.
157.
What is the "exhaust cover of a slide valve? What is its effect upon cushioning and upon exhaust?
What is "minus cover
158.
24
OF "minus lap on the exhaust ?
the exhaust and upon cushioning?
159.
What is its effect upon
How is it affected
What is "enshioning" or "compression" in a steam cylinder? How is it affected by the amount of cover or of minus cover there may be upon the exhaust ? by the exhaust pressure?
What is "
160.
mean effective pressure"? How is its amount ascertained ?
161.
What is a dial vacuum gauge? What is its construction? For what is it used? About what amount should it show when the engine is working all right? What effect has the variations it indicates on the performance of the engine?
162.
Does the vacuum gauge enable you to tell what pressure there is in the condenser, or must you have recourse also to the barometer to arrive at that? How would you ascertain the actual amount of back pressure there is in the condenser ?
What is a barometer ?
163.
What is its construction ? Is a barometer sometimes used
instead of a vacuum gauge ? In what respect does the weather barometer differ from the vacuum gauge barometer ?
164.
The common vacuum gauge and the common steam gauge; in which of them are the graduations marked from atmospheric pressure? Does either of them tell what is the true actual pressure in the boiler or in the condenser ?
165.
Do steam and vacuum gauges vary with the variations of the weather barometer ? When the weather barometer varies from 29 to 31 how much will the vacuum gauge vary and how will that affect the working of the engine? Why?
166.
Vacuum is generally stated as so many inches. What is meant by, say, 20 inches vacuum ? What does that tell us about the absolute pressure of the vapour then in the condenser ?
167.
Is there any limit? Why?
From what depth will a pump draw water?
168.
What is vacuum ? Can vacuum move a piston ? When the temperature of the water in the condenser is 212°, what is the greatest degree of vacuum there can then be in the condenser?
What is a thermometer?
169.
What is its construction? What is the property of matter that is the principle of its construction? What temperatures are regularly noted by careful engineers ?
170.
What is the temperature of (1) melting ice, (2) boiling water, (3) steam about 60 lbs. pressure by the steam gauge, (4) steam about 100 lbs., (5) steam about 150 lbs., (6) smoke in the funnel, (7) water in the hot well?
171.
What is meant by the "conduction" of heat? Give examples of it in the boiler and in the engine?
What is meant by the "convection
"
the engine?
172.
of heat? Give examples of it in the boiler and in
178.
What is meant by "radiation" of heat? Give examples of it in the boiler and in the engine?