Abstract
I classified the fires according to their origins, as A, B, C, D and E. Class A consists of fires originating from small heat origin, for example, cigarette stubs. class B, from a middle and large heat origin, for example, flame, class C, from out-door electric wires which are connected to houses, class D, from spontaneous combustion of chemicals, class E, from the ignition of fats and oils or celluloid.
According to my statistical investigation of fires in Tokyo from 1947 to 1950, fires which belong to class A and C are apt to break out on dry and gusty days, but class D, on hot days. Class B and E have hardly any effect on humidity or wind velocity. On cold days fires originating from B class are frequent because in most homes fire is used frequently for heating.
