274 QUESTIONS. 



[It is an excellent practice to call for a complete analysis of a chap 

 ter, when the pupil is capable of giving it ; or to call upon one to give 

 the several heads, and others to give an account of what is included 

 under these heads. It is well, whenever it is possible, to get up a 

 conversation upon the subject of the lesson. It takes time, but it cul 

 tivates the power of expression, and the valuable art of conversation; 

 it excites an interest in the subject, and it gives the teacher opportuni 

 ties to correct faults in the language of his pupils. The time it takes 

 is not lost, but saved to the best purposes.] 



CHAPTER II. 19. The air? The wind? Give an example of what 

 is meant by elastic. Combustion ? What is it necessary to ? 20. Air 

 composed of? What else? What does oxygen mean? Nitrogen? 

 Azote? Ammonia? [Art. 32, &c. See Index.] Sulphuretted hydro 

 gen? [Art. 40. See Index.] 21. Oxygen? An element? How 

 abundant is oxygen ? 22. Whence cloes oxygen come ? Its tendency ? 

 Its attraction ? Meant by iron s rusting ? Oxide of iron ? What lias 

 happened to the iron ? Where is oxide of iron found ? Oxides ? 23. 

 Why is oxygen called producer of acids ? Acid ? 24. Sulphurous acid ? 

 Sulphuric acid ? 25. Water composed of? 26. Hydrogen? How heavy 

 is it? Meant by elastic? 27. How heavy is oxygen? 28. Common 

 air? 29. Nitrogen? Is it poisonous ? What properties has it ? 30. 

 Is nitrogen always inert? 31. Protoxide of nitrogen? Deutoxide? 

 Tritoxide? Peroxide? Nitric acid? Wonderful about this? How 

 does this happen ? The law of definite proportions ? A law of nature ? 

 Can it be accidental ? How general is this law ? The combining num 

 ber for hydrogen? Carbon? Oxygen? Nitrogen? Sulphur? Iron? 

 Nine pounds of water inacle of? How many pounds of iron combine 

 witli eight pounds of oxygen ? Give an example. Meant by decomposed ? 

 What lias been decomposed? How much iron has been turned into 

 rust? Atoms? How. do atoms combine? How arc the elementary 

 substances represented? What is HO? Nil 3 ? CO 2 ? NO? 

 NO 2 ? NO 3 ? NO 4 ? NO 5 ? 32. Properties of nitric acid? 

 Where is it sometimes formed? 33. Carbonic acid? 34. Wood made 

 of? Combustion ? 35. Flame? 3G. Whence do the light and heat 

 come ? 37. Ammonia ? 38. Where is it formed ? 39. Where do roots 

 get it? 40. Sulphuretted hydrogen ? 41. What is pure air composed 

 of? How much watery vapor does common air contain ? How much 

 carbonic add ? 42. What happens in breathing? What, in place- of 

 oxyuiii, is breathed out? Respiration? Is the quantity of air ren 

 dered unfit for respiration known? How much pure air does a man 

 need ? How many cubic feet does a room, ten feet in each dimension, 



