160 NATURE-STUDY LESSONS. 



13. Have you ever seen limestone burnt on a large 

 scale? If so, describe the process. 



The furnace in which limestone is roasted into quicklime is a lime-kiln. 



14. What use is made of unburnt limestone ? 



15. (a) If there are any limy springs in the neighbor- 



hood observe them to discover if limestone 

 is now being formed. 



Travertine, " petrified moss," is formed by such springs in most parts of 

 southern Ontario. 



{b) Describe the appearance of such limestone. 



(c) Compare it with the old limestone. 



(d) Discover whether there are similar fossils in it. 

 {e) Discover if it will burn into quicklime. 



XLV.-GOLD-BEARINa QUARTZ. 



1. Describe the appearance of quartz. 



2. What does quartz closely resemble in appearance ? 



3. (a) Try to scratch it with your knife and then try 



to scratch the knife with the quartz. 

 {b) Infer from this which is the harder of the two. 



4. (a) Try a similar experiment with a piece of glass 



and quartz. 

 (3) Again, infer which is harder, glass or quartz. 



5. (a) Break a piece of quartz into fine particles ; com- 



pare these with sand. 

 {b) Infer from what kind of rock sand is formed, 

 (c) Compare also with the sand on coarse sandpaper. 



6. Why is sandpaper useful ? 



7. Heat quartz red hot and cool it. Discover whether 

 it will slake like limestone. 



8. Strike a piece of quartz against steel and discover 

 what happens. 



