Ignition of explosive gas mixtures by electric sparks

Minimum ignition energies have been determined for various mixtures of paraffin hydrocarbons from ethane to heptane (excluding pentane) with oxygen-nitrogen atmospheres from air to 100 percent oxygen and for cyclopropane, diethyl-ether, cyclohexane and benzene in oxygennitrogen atmospheres. Values in oxygen-helium atmosphere have been determined for diethylether. In the homologous series of paraffins the minimum energies shift toward the rich side with increasing number of carbon atoms. In this respect the effect of molecular structure for the same number of carbon atmos is small. The smallest minimum energy for ignition (minima of the curves) is practically identical for all the compounds studied.