Report discussing measurements of viscosity made with relative viscometers. These instruments must be calibrated with liquids whose viscosities are known. NBS provides a series of 10 oils for this purpose. Their viscosities range from 0.02 to 450 poises and their temperature coefficients of viscosity range from 2.1 to 9.4 percent per degree C. The less viscous oils are more stable. Correction formulas for errors or conditions are presented.

From Introduction: "This Monograph describes methods and apparatus used at the National Bureau of Standards in connection with several series of investigations of heats of combustion of aircraft fuels [4, 5, 6, 7]."