1886
THE NEW ZEALAND GAZETTE.
[No. 53

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 are 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? Whether 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. Why have some paddle-wheels one or more cast-iron floats in each wheel? With what 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?

101. Whereabout is the centre of the eccentric of a paddle-wheel with feathering floats placed? In that case are the feathering levers on the striking-face or on the back of the float? When the paddle-shaft has an outer bearing, how is the eccentric made?

102. Of what materials are the working-surfaces of a paddle-wheel with feathering floats? How are they lubricated?

103. What is a “disconnecting paddle-engine”? At what place is the disconnecting effected? How is it accomplished? In which of the cranks of a disconnecting engine are the crank-pins fixed?

104. Whether is link-motion valve-gear or the loose eccentric generally used for disconnecting paddle-engines? For what steamers are disconnecting paddle-engines frequently employed?

105. What are expansion joints? Where are they necessary? What attention do they require? Of what should the working-surfaces be made?

106. What omission in the construction of expansion joints may lead to a serious accident when steam is first applied? How is this prevented in the construction of a steam trunnion-pipe for an oscillating-engine?

107. Describe an oil-cup with a siphon worsted. How is the worsted arranged? How is it cleaned? How far down the tube does it extend?

108. Describe a thrust bearing. Which of the surfaces wears? Why are there sometimes a number of oil-tubes for one thrust bearing?

109. What parts of a screw-shaft are generally covered with brass? Why is this necessary? About what thickness is the brass?

110. What is the stern-tube or screw-shaft pipe? Why is a pipe of such a length required? Of what is it made? How is it fixed at each end?

111. What is a lignum-vitæ bearing? How is the wood fitted? Where is such a bearing generally used?

112. How is a screw propeller fixed on the shaft? What means are used to prevent its getting loose at sea?

113. Where are sluice-valves placed? What large sluice-valve is there in almost all screw-steamers? From what position should this valve be worked? Why so? What attention should it receive?

114. With a condensing-engine, what valves or cocks are on the skin of the ship, in the engine-room, and in the stoke-hole?

115. What are the necessary fittings of a marine boiler?

116. With a surface-condensing engine, what cocks or valves are opened some time before the engine is started so as to be ready for starting whenever the order is given?

117. What is a steam-jacket? What cocks are on it? In what engines are jackets most generally used? Do they require to be felted?

118. What parts of an engine or its fittings should be felted or otherwise protected from radiation?

119. What are the small cylinders sometimes fitted on the slide-valve casing-cover of vertical engines? Explain their action. To what are they connected by a pipe? Why so?

120. Name the principal pipes in connection with the engines and boilers of a steamer, and state to what the ends of these pipes are connected.

121. Through what cocks or valves, pipes, and chambers does the water pass on its way from the sea-inlet rose-plate to the water-space of the boiler with a jet condenser?

122. Through what cocks or valves, pipes, and chambers does the circulating water of a surface condenser pass?

123. Through what cocks or valves, pipes, and chambers does the steam pass from the boiler until it is in the form of water in the hot well?

124. Name the pieces of the engine through which the pressure of the steam is transmitted from the piston to the screw propeller. Name them in the order in which they act.

125. What is an air-vessel? How does it act? At what parts of an engine or of its fittings are air-vessels generally applied?

126. What is the construction of a mud-box? Where should mud-boxes be placed? Why are they necessary? How should the space be divided by the rose-plate, and why?

127. What is a trunk-engine? Why has it fallen into disuse?

128. What is an oscillating-engine? For what steamers are oscillating-engines generally adopted? Why? How is the steam conveyed to and from the slide-valve casing?

129. Of what parts does the valve-motion gear of an oscillating-engine consist?

130. For what have geared engines sometimes been used? Of what were the cogs of the large wheel made?