S.V.Gupta Mass Metrology The Newly Defined Kilogram Second Edition
A measurement of quantity leads to the value of the quantity as a product of a pure
number and a well-defined invariant unit. The kilogram—the unit of mass was the
only unit which was embodied in an artefact (Platinum–Iridium cylinder, placed in
specified conditions at the BIPM). This apart from the fact that everybody was to
look for the BIPM for evaluation of their prototype, mass of International Prototype
kilogram was suspiciously changing. This was in contradiction to the condition of
invariance of the unit. The General Conference on Weights and Measures (French
acronym CGPM) decided to revise, along with other SI base units, the definition of
kilogram. The kilogram is such that the value of Plank constant h is 6.626 070 040
Fresh from the University of Allahabad and joining the National Physical Laboratory in 1954, I found myself in an altogether different world. It appeared that what we learnt at M.Sc. level was different than what we need at NPL. There was hardly any detailed literature on mass measurement, except some notes from NPL UK and a Dictionary of Applied Physics. I vow to myself to compile all the available literature on mass metrology. However, it took me another 55 years to complete my dream. My concept was to give every available thing in the literature or my own experience about mass metrology in the form of a book. In the process, I forgot what is required in present times and not necessary for the present genera- tion. For example, I included great details and mathematics about weighing with a two-pan balance. My concept is that very few books are available about mass measurement, so I tried to include a lot of things which might not be needed in the contemporary time. All such superfluous material I have curtailed very much on the recommendation of the Reviewers of the book.
Besides the routine chapters on the unit of mass, mass measurement system in India; two- and single-pan balances their maintenance and testing, I have taken up the various transducers used for weighing and included their testing.