The term calorimetry means the science of heat measurement and is a word which first came into use in the eighteenth century at a time when heat was still being thought of as a fluid called caloric. Similarly, any piece of apparatus with which heat measurements may be made is called a calorimeter. In the previous chapter we explained how the work done by an electric current when it passes through a simple resistor may be measured in joules, and transferred, first to internal energy and thence to heat. So we are now in a position to deal with some elementary methods, based on electric heating, for the measurement of specific heat capacities and specific latent heats. But before proceeding further with this chapter the reader will find it useful to revise the heat definitions and calculations given in chapters 18 and 19.