The size, form and intensity of the gas flame, are regulated by simply turning the stop-cock which admits the gas to the burner or lamp. The flame may at command be made to burn with an intensity sufficient to illuminate every corner of a room, or so low and dim, as barely to be perceived. It is unnecessary to point out how valuable lights of this description are in nurseries, stables, warehouses, and chambers of the sick. From the facility with which the gas flame can be conveyed in almost any direction, from the diversified size and shape which it can be made to assume, there is no kind of light so well adapted for ornamental illumination. The flame of coal gas is of a pure white colour, and of a body full and compact. In large masses, it becomes of the same flickering character which is common to all flames of large dimensions, and is owing to the agitation of the surrounding heated atmosphere. The saving of labour connected with the employment of gas-light, may seem on a small scale to be trifling; but when it is considered that in large manufactories, it is not unusual to find several persons employed for no other purpose than trimming the lamps or setting and snuffing the candles of the establishment, the advantage gained on this head by the use of a species of light which require no sort of attention whatever, cannot but appear very considerable. The cleanliness of the gas-lights is also a consideration of no small importance, they are attended with none of that spilling of oil, and dropping of grease, which makes the employment of oil-lamps and candles so injurious in many warehouses, shops and private dwellings. The flame of a gas-light compared in point of brilliancy to that of a candle, is as the flame of a common oil lamp, compared to the flame of a lamp of Argand. The difference between a street, on the night of a general illumination, and any other night when the street is under the dull glimmering light of the ordinary oil lamps, is scarcely more remarkable, than the difference between a street lighted by gas, and one lighted by oil. While the ordinary oil lamps may be said merely to serve the purpose of making “_darkness visible_,” the gas-lights really dispel the dominion of night, and diffuse a body of light so wide-spreading and intense, as almost to rival the clearest moonshine.