Abstract: This invention relates to a method of and apparatus for determining the calorific value of a sample of combustible material. The apparatus consists of a calorimeter bomb which is located in a temperature insulated enclosure and includes temperature sensors which are located in the wall of the bomb with electrical terminals for firing the bomb and monitoring the temperature changes in the wall of the bomb passing through the base of the bomb and enclosure for connection to a computer. The method consists in monitoring temperature changes in the wall of the bomb when it has been fired to burn a sample located in it by means of a computer.