He maintains, in opposition to Sir Humphry Davy, that the Davy lamp acts by its heat and rarefaction, and not from Sir H. Davy's theory, that flame is cooled by a wire-gauze covering. He shows, by a simple experiment, that the Davy lamp is not safe in a current of hydrogen or carburetted hydrogen gas, and that many lives may have been lost from the confidence of miners in its perfect safety. A current of hydrogen or carburetted hydrogen gas steadily directed on the flame of the lamp from a bladder and stopcock, by cooling the wire gauze, brings the flame of the lamp through the gauze to the mouth of the stopcock, (even should there be six folds of gauze intervening.) He shows also, by immersing the lamp, when cold and newly lighted, into a jar of dense hydrogen or carburetted hydrogen gas, or an explosive mixture with atmospheric air, that explosion takes place inside and outside of the lamp; whereas, when the lamp has burnt sufficiently long to heat the wire gauze, no explosion takes place on the outside of the lamp. These experiments appear incontrovertible in support of his theory, which is, "that the wire gauze is merely the rapid receiver and the retainer of heat, and that it is the caloric in its meshes which prevents the flame of the lamp from being fed by the oxygen of the atmosphere on the outside."
The experiments of Libri, showing that flame is inflected by metallic rods, and that "when two flames are made to approach each other, there is a mutual repulsion, although their proximity increases the temperature of each, instead of diminishing it," support Mr. Dillon's theory—the inflection being occasioned by the rarefaction of the air between the rod and the flame, the latter seeking for oxygen to support it in a denser medium, the two flames repelling each other for the same reason, and not from any mysterious and "repulsive effect of the wires of the gauze tissue." Mr. Dillon increases the heat of the lamp, and places on it a shield of talc to protect it from a current, and, upon his theory, the shafts or workings of iron and coal mines may be lighted with gas with perfect safety, protecting the flame with wire gauze and a circular shield of talc.
EPITAPH ON A FRENCH SCOLD.
Ci git ma femme; ah! qu'il est bien
Pour son repos et pour le mien.