DIFFERENT RACES OF MANKIND. 37 



" Questions. 



In what form does the matter called 'electric show itself? 



How may it be produced ? 



What other substances exhibit similar effects 1 



What is the nature of lightning 1 ? 



What do we call the noise that follows the flash ? 



W^hat is the effect of lightning when it strikes an object ? 



In what respect are thunder-storms beneficial 1 



How may buildings be secured from injury by lightning? 



Why is a house surrounded by high trees rarely struck by 

 lightning ? 



Is it then prudent or imprudent to take shelter under trees 

 in a thunder-storm 1 



How may the distance of lightning be calculated ? 



On what principle is that calculation made ? 



What is the ignis-fatuus, or Will-with-a-wisp ? 



W^here is it most frequently seen 1 



What does it consist of ? 



What kind of motion has it ! 



What are the bodies commonly called falling stars ? 



What appearance have they ? 



Is their motion ever attended with any sound ? 



What kind of appearance is the aurora borealis or northern 

 light? 



What is the cause of it 1 



LESSON IX. 



DIFFERENT RACES OF MANKIND. 



THE whole world is supposed to contain about 

 700 millions of human inhabitants. Of those, 

 such as dwell together in a country, and are of 

 the same general structure, colour, language, and 

 manners, form one people, or nation. 



Each of the principal divisions of the world is 

 D 



