2l8 



Common Science 



FIG. 122. Which should he choose to connect the broken wires? 



work ; then you can't get a shock," added another member 

 of the family. 



" That's a good idea," said the wife, " but wet the gloves, 

 then you will have the double protection of the water and the 

 cloth." 



The man laughed and went to work on the socket. He 

 did not get a shock. Which advice, if any, do you think 

 he followed? 



Inference Exercise 

 Explain the following : 



311. A red postage stamp looks greenish gray in the green light 



of a mercury-vapor lamp. 



312. Cracks are left between sections of the roadbed in cement 



auto highways. 



313. Electricity goes up a mountain through a wire. 



314. It is impossible to stand sidewise against a wall on one foot, 



when that foot touches the wall. 



315. A charged storage battery will run an electric automobile. 



