In this thesis the spontaneous heating of coal is considered to be the phenomena in which a sufficiently large quantity of coal (often many tonnes), will rise from ambient temperature and eventually go on fire if exposed to air. It has been acknowledged for many years that the major source of heat in this process is due to the oxidation of the coal itself. It is also acknowledged that extraneous sources of heat, i.e., the oxidation of iron pyrites, can play an important part in this process. But the major subject of this thesis is concerned with the effect of heat from coal oxidation and an experimental method whereby the full process of spontaneous heating can be examined in the laboratory.