A YEAE IN SCIENCE 51 



Allow it to burn in the tube for a minute, then remove 

 it and mix the lime water with the gas in the tube 

 by shaking. What is the effect of the gas on the lime 

 water? Then what must this gas be? (See Exercise 6.) 



Rinse the test tube with water. Again place some 

 lime water in it. Light the pine splinter and thrust it 

 into the test tube. Remove the splinter and shake the 

 lime water. What change do you note in the lime 

 water? Does wood contain carbon? 



Place a few pieces of marble in a clean test tube. 

 Pour on it a little dilute hydrochloric acid. What hap- 

 pens? This is a chemical action between the marble 

 and the acid. Over the mouth of this test tube place 

 the mouth of another to collect some of the gas given 

 off. Remove the second test tube, pour into it some 

 lime water and shake. What is the effect on the lime 

 water? What does this indicate? Hydrochloric acid 

 contains no carbon. Does marble? 



What are the properties of carbon as found in char- 

 coal? In what substances did you find carbon? What 

 other forms of carbon do you know? 



Exercise 28. Phosphorus. (Demonstration.) 

 Object: To determine some of the properties of 

 phosphorus. 



Apparatus 



Yellow phosphorus Forceps 



Ivcd phosphorus Knife 



Evaporating dish Filter paper 



Directions: (('ATTION Yellow phosphorus must be 



