462 GENERAL SCIENCE 



22. If the sun does not shine for several days, why do sailors 

 say they are reckoning longitude by dead reckoning? 



23. If you travel from New York through San Francisco to 

 Peking, China, how many times would you change your watch? 

 Would you lose or gain time? How much? 



24. Are there any places where you would change time from one 

 day to another? Why? 



25. Why was it necessary to have a place from which to reckon 

 time? 



26. Find two places less than 100 miles apart where, the people 

 in one place called the day Thursday and the people of the other 

 place Wednesday? 



27. What is the difference between sun time and standard time? 



28. Why do we not reckon time by sun time? 



29. How are we able to tell the correct time for any section of 

 the country? 



30. Why is latitude important? 



31. What kind of climate would you expect to find in 30 north 

 latitude, 60 north latitude and 10 north latitude? 



HEAVENLY BODIES 



Ancient Knowledge. From time immemorial man has studied 

 the universe. He has been interested in the stars, the moon and 

 other heavenly bodies because they seem to have a certain element 

 of mystery. The Chinese claim to have made many discoveries 

 several thousand years B.C. Shepherds of olden times watched, 

 studied and made records of things they saw in the heavens. The 

 Greeks did much to classify knowledge which had been gained regard- 

 ing the universe. 



The Sun. One of the heavenly bodies which is familiar to us 

 is the sun which is about 91 to 93 millions of miles from the earth. 

 The light given off from the sun is equal to that of 6000 wax candles 

 at a distance 1 foot from the eye. It would require 600,000 full 

 moons to produce a day as brilliant as a day produced by the sun- 

 light. The r.un is really blue. The sun, probably because of our 

 atmosphere, has a tendency to appear red, since red rays pass 



