X. Radiation in explosions of coal-gas and air

In the first part of this paper results of experiments are given on the radiation emitted during the explosion and subsequent cooling of mixtures of various strengths and densities of Cambridge coal-gas and air. Bolometric measurements were made of that part of the radiation from the hot gaseous mixtures which was transmitted through clear plates of fluorite, quartz, plate glass, and water (contained between two plates of glass). The fluorite (6 mm. thick) transmits very approximately 95 per cent, of the total radiation emitted by the gas; the quartz (also 6 mm. thick) transmits about 70 per cent, of the radiation from water vapour and cuts off a very large proportion of that from CO2 ; the water cell transmits practically only luminous radiation. It has been therefore possible to estimate fairly accurately the total radiation emitted by the gas, and, roughly, the proportions emitted by water vapour and by CO2 , and also the amount of energy in the luminous radiation. The radiation emitted in the explosion of a 25-per-cent, mixture of hydrogen and air has also been measured. The second part of the paper consists of an investigation into the diathermancy and emissive power of the hot gaseous mixture after explosion. The conclusions drawn from these experiments offer an explanation of many of the peculiar results given in the first part.