SCIENTIFIC READIXGS. Ill 



12. Were the ancients acquainted with magnetic at- 

 traction ? 



13. Why or through what principle does water ascend 

 to the branches of trees by means of their roots ? 



14. To what cause is the cohesion of bodies attri- 

 buted ? 



15. What is the opinion of Sir Richard Phillips in 

 regard to capillary attraction ? 



16'. What is the chief antagonist to cohesion. 



17. What kind of attraction is that when the force 

 acts on atoms of the same species ? 



18. When the force of attraction acts on atoms of 

 different substances, what is it then termed ? 



19. To what is the spherical shape of drops of quick- 

 silver attributed ? 



20. How many kinds of chemical attractions are there? 



21. How do bodies generally combine ? 



22. When a chemical combination has been effected, 

 can the bodies combined be separated by mechanical 

 means ? 



23. What is simple and what compound affinity, and 

 give an example of each? 



24. What is the chief principle of action in chemical 

 combinations? 



25. How far will a body fall near the earth's surface 

 during the space of five seconds, of seven seconds, and of 

 ten seconds ? 



26. What will be the quantity of descent of a body 

 during the third second, the sixth second, and the ninth 

 second of its fall ? 



27. How long would a body take to fall through a 

 space of 5OO feet, of 1000 feet, and of 1500 feet? 



CALORIC, HEAT, FIRE. 



28. W T hat would have been the state of man without 

 fire? 



29. Is fire a real substance ? 



30. What is Fire? 



