Simple flow meter and viscometer of high accuracy for gases

Table 2 was incorrect due to a sign error of the viscosity ratios CN2(gas) and a misinterpretation of literature values for helium, nitrogen and argon. The corrected table is given in the PDF file. For helium, the corrected measured value differs from the ab initio calculated value of (19.823 ± 0.006) µPa s by twice the combined uncertainty of 0.05%.