2 .LABORATORY EXERCISES. 



b. Compare the smell of the phosphorus 

 with the smell of the match tip in 

 i (above). What, therefore, is 

 one of the substances found in the 

 head of a match? 



4. (Dem.) After the water has been removed 



from the phosphorus by means of 

 blotting-paper, what do you observe? 

 In what other part of this experiment 

 have you observed a similar substance? 

 Why is phosphorus kept under water? 



5. (Dem.) What is the result of rubbing a 



piece of phosphorus between two sticks 

 of wood? What causes this result to 

 take place? (To aid in answering this 

 question rub together briskly your two 

 hands and note the feeling.) (When 

 phosphorus burns it combines with the 

 oxygen gas found in the air and forms 

 oxid of phosphorus.) How was the 

 phosphorus made to combine with oxy- 

 gen? 

 B. Sulphur. 



1. Examine some common sulphur. What 



are its physical properties? What evi- 

 dence of sulphur can you see near the 

 match tip? 



2. Light another match, and after the white 



fumes have disappeared, smell cautiously 

 of the burning match head. (This gas 

 is called oxid of sulphur.) What kind 

 of odor has the gas? 



