rate, 0.09 mils per second (approximately 1" in three hours). For some- 

 what less critical demands a pull rate 10 times faster is used, with a short- 

 ened after-heater or none at all. 



If it is desired to reproduce a resistivity obtained in the zone leveler, 

 it is very convenient to reuse the solidified zone containing the impurity 

 addition that yielded the desired resistivity. This solid zone, if undam- 

 aged (when cut from the finished ingot), will contain all of the sohite 

 that was not deposited during the ingot run. When it is remelted next 

 to a seed the solute will redissolve into the liquid to yield very nearly 



