Both artefacts are in contrast in vacuum and in air. By evaluating The 2 artefacts of equivalent nominal weight, the large volume variation demonstrates the air buoyancy and thus ends in a really accurate determination of air density. The buoyancy artefacts are mostly employed for the M_one vacuum mass comparator. https://bailing-wire91112.spintheblog.com/31487209/detailed-notes-on-bailing-wire