GENERAL APPARATUS AND MANIPULATION 193 



ing the ten pieces together on a microbalance, and then observing 

 the displacement given by each piece placed separately on a pan. 

 The sum of the individual displacements divided by the total weight 

 gives the sensitivity. The process must be repeated on the other pan 

 if both arms are to be calibrated. The balance will accommodate 

 larger weights if a tare is used as a counterbalance. 



