100 LABORATORY LESSON& IN GENERAL SCIENCE 



effervescing liquid a glass rod having a drop of clear lime- 

 water on its lower end. This is the usual test for carbonates.) 

 Repeat the test, using in turn a small lump of marble, and 

 then one of limestone. Try bits of egg shell, and of any 

 other shells at hand. Test any fragments of rock provided, 

 and pieces of old mortar. Be sure to note about what por- 

 tions (if any) of the marble and of the limestone fail to dis- 

 solve in the acid. Account for any such failure. 



