138
THE HONGKONG GOVERNMENT GAZETTE, MARCH 11, 1910.
83.
How is an engine heated up before starting? What precautionary examinations are made before starting?
84.
What is an interceptor or catch-water? Where is it fixed, what is its construction, how does it act, and what attention does it require ?
85.
Describe an air-pump bucket, with its valve or valves and its packing. Of what are the valves generally made?
86.
Of what materials are air-pump rods made? Why?
87.
What is the racing of the engine? When does it occur? What danger attaches to it? What is done to prevent it?
88.
When under way, when the air-pump bucket is at the top of its stroke, at what height is the water in the condenser ?
89.
What is meant by the " pitch" of a screw propeller? How is it measured ?
90.
Explain the difference between a "right hand" and a "left hand" propeller, and state how each of them revolves.
91.
What is the slip of a screw propeller? How is its amount expressed in figures?
92.
Which of the valves about engines and boilers have to be worked by hand, which of them work self-actingly, and which are worked by the motion of the engine?
93.
Why is soda sometimes put into a boiler, and how is it put in when under way? What is the kind of soda used?
94.
Tallow cups for cylinders were sometimes made with two small cocks, or with only one- small cock, or with one large hollow plug cock, or with one small cock and a valve; which of these is suitable for a high-pressure cylinder, and which for the cylinder of a condensing engine? Describe how the cup with only one small cock is used. What is now generally used instead of these? How has this change come about?
95.
Does a cylinder escape valve, self-acting, allow all the water to escape, if not how much is left in the cylinder?
96.
What is a Steam Lubricator" (sometimes called an Impermeator)? Explain its action. To what part of the engine is it connected? Will throwing cold water over it
make it work faster or slower? Describe the one used in your last steamer?
97.
A common paddle wheel; of what is the centre made? Of what are the arms formed? What is the form of the bolts which attach the floats to the arms? How are the arms attached to the centres ?
98.
With what
Why have some paddle wheels one or more cast-iron floats in each wheel? engines are these most required? At what part of the circumference are they placed?
99.
Why are paddle wheel floats sometimes made of different breadths in the same wheel ? With what description of engine is this most needed ? Where are the broad floats placed and where are the narrow floats placed in the circumference of the wheel?
100.
What difference is there between a radial paddle wheel and one with feathering floats? What is the object of feathering floats? Are all the eccentric rods attached in the same way, and are they all of the same form?
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