126. Explain the barometer. Relate the incident given by Dr. Arnot.
127. Why would not a water-barometer answer? What is said of the barometer as a measurer of heights? How is the boiling point influenced by the amount of the air's pressure? Give the experiment with ether.
128. State the experiment with the flask. What would happen to liquids if the atmosphere were removed from the earth? Explain the operation of the syphon by Fig. 117.
129. Explain what is represented by Fig. 118.
130. Explain the uses of the syphon. Explain the operation of the Cup of Tantalus.
131. How are intermitting springs accounted for? Explain the operation of the common pump.
132. Why does the water rise in the pump? How is sucking done? Explain the forcing pump.
133. Explain the fire-engine.
CHAPTER X.
134. What is said of the universality of motion? What of attraction as a cause of motion? What of heat? What of chemical agencies? What of life?