NATURE-STUDY LESSONS. 161 



9. Examine a piece of gold-bearing quartz to discover 

 other minerals than the quartz. 



Such generally has gold and iron pyrites. 



10. What is the color of each of these ? 



1 1. Discover which is harder, your knife or iron pyrites. 



12. Discover which is harder, quartz or iron pyrites. 



1 3. Powder and strongly heat some iron pyrites. Des- 

 cribe what happens. 



14. (a) Observe the smell while the pyrites is being 



roasted and infer what substance is being 



given off. 

 (fi) Describe the material left and note its color. 

 (c) What has passed off" from the pyrites ? 

 {d) Why is the powder that is left rusty ? 



15. Try to cut a piece of gold with a knife and to 

 flatten it with a hammer. 



A metal which can be beaten or rolled out without breaking at the 

 margin is said to be tnalleable and possesses the property of maUeability. 



16. Compare gold and iron pyrites as to hardness and 

 malleability. 



17. Heat gold and compare its smell then with that of 

 iron pyrites when heated. 



18. Select pieces of quartz, pyrites and gold of nearly 

 equal size and discover which is heaviest and which is 

 lightest. 



19. Weigh a bit of quartz, first in air, then tied by a 

 hair to the beam of the balance in a glass of water. 

 Subtract the weight in water from that in air. Divide 

 the weight in air by the difference between the two 

 former weights. The quotient will be the weight of the 



