HOW MOUNTAINS ARE MADE 195 



Experiment 71. Distillation of Petroleum. 



Apparatus: Hard glass test tube 8" XI", cork stopper, 

 with one hole, to fit, glass tube \" bent at right angles, four 

 U -tubes having side tubes, cork stoppers to fit, rubber tubing 

 to connect glass tubing and U -tubes, ring stand, burner, bat- 

 tery jar, 6"X8". 



Materials: Crude petroleum. 



a. Fill hard glass tube one fourth full of crude petroleum, 

 and connect it to the U -tubes with pieces of rubber so that the 

 distillates will have to pass through one after the other. Put 

 the U-tube which is farthest from the heat in a battery jar 

 filled with water about 20 C. Leave the free side tube of 

 this last U-tube open to the air. 



b. Heat the petroleum very gently at first, and then more 

 strongly. The material which has the lowest boiling point 

 will go the farthest before it condenses. Continue to heat 

 until the petroleum solidifies, and then disconnect the hard 

 glass tube from the first U-tube. 



c. Break the hard glass tube, and examine contents. What 

 is it ? Describe the various products which you have obtained. 

 Place them in evaporating dishes, or saucers, and try to burn 

 them. Compare them with lubricating oil, coal tar, gasoline, 

 and kerosene. 



139. How MOUNTAINS ARE MADE 



Mountains have been formed in two general ways, folding 

 and faulting. Both these methods, however, are due to one 

 cause, the cooling of the earth. We may consider the earth, 

 like any other hot body, to have cooled on the outside first. 

 The cooling of the material inside continued, and at the same 

 time the contraction which accompanies cooling took place. 

 Thus the outside crust became loose and was not in close 



