Weighing by Double Substitution by National Institute of Standards and Technology (SOP4–2019)

Recommended Standard Operating Procedure for Weighing by Double Substitution, SOP4,2019, part of NISTIR6969–2019. Corporate primary publication; no individual authorship inferred. Precise locators: p1, Purpose, comparison twice with a known standard and response calibration using a sensitivity mass; pp6–8, actual sequences/observation instructions; §3 and uncertainty section, buoyancy and density contributions. The article's separate equally spaced four-reading cancellation example is an original simplified model, not a transcription of this full procedure.

Additional locators in the 2019 SOP4: p. 3, Summary, sensitivity addition during the latter two observations; p. 7, Table 5, loads S, X, X+sw and S+sw; p. 8, observations 2.5.2.1–2.5.2.6; pp. 9–10, calculations and buoyancy treatment.