Mercurous Sulfate: Mercury Dissolved in Sulphuric Acid with Gentle Heat (Thorpe, 1912)

Mercurous sulphate, the white salt of the Clark and Weston standard cells: 2 parts of mercury dissolved in 3 parts of sulphuric acid with the help of gentle heat. Water turns the salt first into a basic sulphate and finally into the oxide, so it is kept from water. Unknown: how the salt is taken out of the acid. Thorpe does not give it. Not given: the acid strength. Source: T. E. Thorpe, Dictionary of Applied Chemistry vol. III (1912), p. 452. Picture: the book's text.