Calibration of meter line standards of length at the National Bureau of Standards

.The results of intercomparisons of t he t otal lengths of several meter bars and of calibratlOns ?f the s ubllltervals of some of ~hese bars for t he past twenty years are reported . Inf?rmatlOll both on t he dep;ree of stablhty of these standards and on the precision wi th which such measurements can be repeated was obtained. The r esults are critically analyzed and comments made as to the precautions necessary in t he precision cOIJlparisolls or'line standards of length.