Precision of Line Standards

Abstract

M. PÉRARD'S justification of the metrologist's claim of being able to compare two line standards with an error not exceeding ± 0.2 is based entirely on the degree of concordance observed in practice when large numbers of readings are taken in all possible positions. Equally so, we find when we analyse the purely interferometric data for the number of waves contained in an optical gauge of a metre length, the concordance between the individual results is even more striking.