The presence of oxygen in spring-water, though not always a guarantee of purity, is very good indication of such, as the organic matter most injurious in drinking water is that most readily oxidized, and the presence of free oxygen indicates an excess above the quantity necessary to effect such oxidation. However, the presence of oxygen in water is objectionable in the case of waters flavored with essential oil or other principles liable to change by oxidation.

Waters containing ferrous compounds can only be prepared successfully by the careful exclusion of oxygen in every stage of the manufacture.

Mr. B. Bruce Warren, at a meeting of the Society of Arts, read an interesting lecture on the preparation and manufacture of carbonated waters. One of the principal points we herewith present:

"From certain experiments which I have made and am still carrying out, it would appear as if this oxygen contained in the water acquires an enhanced chemical activity under certain circumstances, and although I am not able to prove that it becomes ozonized, I am certainly of opinion that the oxidation of oil of lemon in lemonade is in a great measure the cause of the deterioration where sound and genuine ingredients have been used. Other substances liable to change by oxidation may, of course, alter in the same way. In the ordinary manufacture of carbonated waters belonging to the saline class, oxygen gas is not likely to do any harm, but it is impossible to regard its presence with indifference where essential oils or other easily oxidized materials are employed. The seriousness of air-impregnated water has not escaped the attention of manufacturers, and a system of bottling water free from atmospheric air has been recently perfected".

For a remedy for removing the atmospheric air from water we refer to the article on the "Removal of Atmospheric Air" in another chapter, which explains its injurious effects on carbonic acid and carbonated beverages.