Measuring Planck's constant and monitoring the kilogram at NPL

Summary form only given, as follows.We are commencing measurements aimed at a definitive value for h with an uncertainty of about 1 in 10/sup 8/ and a target completion time of June, 1996. Many incremental improvements to the apparatus have enabled us to obtain a resolution of 1 in 10/sup 8/ (including the measurement of gravitational acceleration). Investigation of systematic errors is beginning.