A Measurement of R_c using a Multiple-Tagging Method                           
  
We present a new measurement of Rc, the branching fraction of the Z to         
primary charm quarks, using a novel multitag method.  Four tags, based on      
kinematic and lifetime variables, are used to separate light from charm        
from bottom quark jets.  The rates of single- and double- tagged events        
are used to measure many of the tag efficiencies and some of the               
interhemisphere tagging correlations, greatly reducing the overall             
systematic errors.                                                             
  
 Parallel session :5<br>7              
 Plenary  session :6a<br>3