In determining it, it is first converted into sulphuric acid, and then precipitated and weighed as barium sulphate.
Moreover, the use of hot concentrated hydrochloric acid causes a loss by dissolving barium sulphate.
Six parts by weight of pure glycerine, four parts by weight of water, two parts of barium sulphate, and one part of sugar.
Readings were standardized for 100% reflectance with barium sulphate.
The reference was a barium sulphate standard plate.
Pressed barium sulphate was used as a working standard for the calibration of 100% reflectance.
Supplies of barium sulphate, mainly from home sources, are sufficient to meet all requirements.
