182 NATURE STUDY 



giving them time always to observe their specimens, and 

 to think out the answers, but not allowing them to 

 answer orally. Then giving them each paper, let them 

 write all that they can. 



For mica the following questions might be used: 

 What is the color of your specimen? Hold it up to 

 the light. Has it the same color ? Try to scratch it 

 with your finger nail. Is it hard or soft? Separate it 

 into thin layers. Hold these to the light. What can you 

 see through it ? 



Teach the words '' transparent," " structure." Teach 

 them the uses of mica, and show them how it happens to 

 be in the soil. It is usually perfectly easy to get a series 

 of specimens of gneiss and mica schist, showing all the 

 transitions from, the hard to the softer rock and to soil. 



Questions on quartz pebbles : Scratch it with your fin- 

 ger nail, with a penknife. Try to scratch glass with it. 

 Is it hard or soft ? What shape ? Why ? How hard ? 

 What color ? Is it transparent ? Let the light shine on it. 

 Does it shine like glass, or is it softer like pearls ? What 

 is its structure ? Does it break regularly or irregularly ? 



Review " structure " and " transparent." Teach the 

 words "translucent," "opaqiie," ''lustre." Teach part 

 of the scale of hardness, namely, 1, 2, 5, 7. 



Procure as many different kinds of quartz as possible. 

 Mix up with these crystals of rock salt, rock candy, cal- 

 cite, fluorite, feldspar, anything, indeed, similar in ap- 

 pearance to quartz, and let them learn to distinguish one 

 from the other. This is easily done by testing the hard- 

 ness. The peculiar crystalline structure of quartz should 

 be thoroughly taught. 



