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Tea and coffee were adulterated with sand, chicory, and spent grounds treated in ferrous sulphate and sheep’s dung.

Faraday compared the intensity of its action with that of ferrous sulphate, and this led to an explanation of the diurnal variations of the compass-needle based on the sun's heat diminishing the magnetic permeability of the oxygen of the air.

From this last term comes the modern melanterite, native hydrous ferrous sulphate.

The precipitants in use are: ferrous sulphate, charcoal and sulphuretted hydrogen, either alone or mixed with sulphur dioxide; the use of copper and iron sulphides has been suggested, but apparently these substances have achieved no success.

Or Gutzkow’s method of precipitating the metal with ferrous sulphate may be employed.