Page:On the Atmospheric Bude-Light.pdf/3

Rh afterwards adopted for the House of Commons. Difficulties, however, occurred in the practical working of this light, and Mr. Gurney determined on still further prosecuting his experiments; and the result of which was, the production of the present, or what may be called the Atmospheric Bude-Light.

The mechanical arrangement by which the light is produced consists of a series of concentric rings, perforated on the upper surface for the escape of the gas, placed at equal distances from each other, and so arranged as to regulate the quantity of atmospheric air, and to communicate by conduction and radiation sufficient heat to raise the temperature of the gas to a given point, so as to effect the separation of its charcoal immediately on its leaving the burner, and then, by an arrangement above, to bring fresh atmospheric air to the proper points of the flame. A perfect lamp will deposit the charcoal in the flame the instant it passes the jet. If so imperfect as to deposit too soon, charcoal will be found in the rings; if too late, then high up in the flame. There is a point of accuracy required which practice has determined. This mechanical arrangement brings about a series of chemical changes involved in the evolution of light and heat which are very interesting. The rapidity of chemical union governs the respective quantities of heat and light. By a too rapid combination, heat without light may be produced.

By the concentration of a mass of light a powerful illuminating effect can be diffused over the whole apartment, without shadows incidental to many lights, which may be softened down by glass shades to any pitch, and tinted, if desired, with any colour.

Its economy has been proved to be very great. The evidence given by the scientific gentlemen examined before the Committee of the House of Commons proves that, for the same quantity of light, the saving for using the Bude burner is equal to fifty per cent.

The Committee, in their report to the House, state that the saving effected upon the lighting the House by the introduction of this light was 484l. 9s. per session. Its effect in the different churches where it has been placed is most excellent. Clapham New Church is lighted by one burner of eleven inches diameter, which is composed of five concentric rings.

The importance of ventilation has, until of late, been very much neglected, notwithstanding all that has been said on the subject by our medical gentlemen of eminence. An ordinarily sized person breathes about ten cubic feet of air per hour, and contaminates by the exhalations from his body as much more; and one oil-lamp consumes about forty cubic feet of air in the same time. So that, in a room filled with twenty persons and lighted by four oil lamps, as much as 360 cubic feet of air per hour is rendered not only unfit for respiration, but absolutely poisonous. The air thus heated