June 1, 1999
      
                  
        
  Author(s)
  James W. Schmidt,   Y Q. Cen,   Robert G. Driver,   Walter J. Bowers Jr.,   J C. Houck,   S A. Tison,   Charles D. Ehrlich
 
       
            
    
    
        Primary pressure standards in the atmospheric pressure range are often established using mercury manometers. To a lesser extent controlled-clearance dead-weight testers in which one component (normally the piston) has been dimensionally measured have also