ABSTRACT
Everyone is familiar with the facts that the flame of a candle, an oil lamp, or ordinary coal-gas is more or less luminous, while burning hydrogen, spirit of wine, or gas mixed with air, as in the Bunsen burner, gives so little light that such a flame in broad daylight is scarcely perceptible and in sunlight is actually invisible. Sir Humphry Davy was the first to enquire systematically into the source of light in flame, and in 1816 he put forward the opinion that the production and ignition of solid particles within the flame itself is the cause of the light. The earlier mantles were very liable to shrink and suffer contortion whereby they were often withdrawn from the hot part of the flame and so produced less light. The mantle industry is only one of many examples which could be quoted of the ultimate practical application of the results of purely scientific research to common industrial purposes.
