v. A small voltaic battery standing on the stool with glass legs, s s, and capable of heating a thin length of platinum wire about two inches long, and bent to form a point between the conducting wires, w w.—N.B. The voltaic current can be cut off at pleasure, so as to cool the wire when necessary. a is the prime conductor of an ordinary cylinder electrical machine. b is the wire conveying the frictional electricity to the conducting wires of the voltaic battery, where the point p being the sharpest point in the arrangement, delivers the electrified and ozonized air.
Ozone is insoluble in water, and oxidizes silver and lead leaf, finely powdered arsenic and antimony; it is a poison when inhaled in a concentrated state, whilst diluted, and generated by natural processes, it is a beneficent and beautiful provision against those numerous smells originating from the decay of animal and vegetable matter, which might produce disease or death: ozone is therefore a powerful disinfectant. The test for ozone is made by boiling together ten parts by weight of starch, one of iodide of potassium, and two hundred of water; it may either be painted on Bath post paper, and used at once, or blotting paper may be saturated with the test and dried, and when required for use it must be damped, either before or after testing for ozone, as it remains colourless when dry, but becomes blue after being moistened with water.
Paper prepared with sulphate of manganese is an excellent test for ozone, and changes brown rapidly by the oxidation of the proto-salt of manganese, and its conversion into the binoxide of the metal.
Ozone is also prepared by pouring a little sulphuric ether into a quart bottle, and then, after heating a glass rod in the flame of the spirit lamp, it may be plunged into the bottle, and after remaining there a few minutes ozone may be detected by the ordinary tests.
NITROGEN, OR AZOTE.
Νιτρον, nitre; γενναω, I form; α, privative; ζωη, life. Symbol, N; combining proportion, 14. Also termed by Priestley, phlogisticated air.
In the year 1772, Dr. Rutherford, Professor of Botany in the University of Edinburgh, published a thesis in Latin on fixed air, in which he says:—"By the respiration of animals healthy air is not merely rendered mephitic (i.e., charged with carbonic acid gas), but also suffers another change. For after the mephitic portion is absorbed by a caustic alkaline lixivium, the remaining portion is not rendered salubrious; and although it occasions no precipitate in lime-water, it nevertheless extinguishes flame and destroys life." Such is the doctor's account of the discovery of nitrogen, which may be separated from the oxygen in the air in a very simple manner. The atmosphere is the great storehouse of nitrogen, and four-fifths of its prodigious volume consist of this element.
Composition of Atmospheric Air.
| Bulk. | Weight. | ||
| Oxygen | 20 | 22.3 | |
| Nitrogen | 80 | 77.7 | |
| --- | ----- | ||
| 100 | 100. |