THE SOLAR SYSTEM 13 



Are there other worlds besides ours t 



When are they to be seen ? 



What is their appearance ? 



Do the heavenly bodies stand still or move ? 



What is the world in which we live called ? 



WTiich are the bodies that give, or reflect, light? 



Of what shape are they ? 



What are they called in consequence *? 



Is it probable that any of the heavenly bodies are inhabited ? 



What is the space called through which they move 1 



What is the diameter of an orb ? 



What is the axis of an orb 1 



What is the meaning of circumference ? 



LESSON II. 



THE SUN THE MOON THE SOLAR SYSTEM. 



THE sun is the largest of all those orbs which 

 we behold in the heavens. It is supposed to be 

 surrounded by a luminous atmosphere, from which 

 light and heat are transmitted to the earth which 

 we inhabit, as well as to the other orbs, which all 

 move round the sun as their centre. The diameter 

 of the sun is 888,000 miles; a space so vast that it 

 is difficult to convey a correct idea of it. If a man 

 were to travel at the rate of 100 miles a day, he 



