The authors describe thedevelopment

The authors describe the
development of this instrument, with a working volume of 8mm×8mm×0.1mm. The instrument uses
a co-planar air-bearing slideway tomove the sample. It also uses a novel vertical displacement measuring
probe, incorporating an air bearing and an electromagnetic mass-offsetting mechanism. The motions
of the slideway and the probe are measured by laser interferometers, thus, ensuring traceability of the
measurements to the definition of the metre. A description of the main sub-systems that make up the
instrument is given and very preliminary results are presented.