The ignition process was studied in this paper, which was particularly connected with the drying process of refuse in the statical characteristics of refuse incinerators. Because of variety in refuse forms to be supplied to the incinerators, a physical model was composed, assuming that refuse was the layers of piled up refuse elements with uniform forms, and the ignition curves of the layers were drawn on the basis of the above model after a mathematical model was formed. The upper part of the curves was altered so that it suits to actual endothermic and heat velocity distribution on the assumption of temperature distribution in the incinerators at their inlet side. No particular alteration was made in their middle part, then the ignition curves were changed to almost straight lines inclined downward. Unburnt and refuse under firing were wrapped by ash and uncombustibles, so the lower part of the curves was only studied as a imaginary solid model by the two methods of finite element method and simple analytical one, and conversion was made into equivalent reduction in combustion temperature. 15 refs., 7 figs., 2 tabs.