One of these devices is known as an ozone air purifier.
Internally, each purifier is filled with ranges of wooden trays or sieves A, made in the form of purifiers.
The gas in the connecting pipe between the second and third purifier will be found to contain 400 grains of sulphuretted hydrogen and 20 grains of carbon disulphide.
The finding of any traces of carbon dioxide in the gas between the first two boxes is generally the signal for a new clean purifier being put into action, and the first one shut off, emptied and recharged with fresh lime, the impregnated material being sometimes sold for dressing certain soils.
Nusku-Girru is by the side of Ea, the god of water, the great purifier.