If we dip our hand into water which has been standing near a fire for some time, we might say that the water is hot. When the hand is dipped into melting snow one might say that the mixture is cold. Later on, when the water has been removed from the fire, one should find that it is less hot; likewise the water from the melted snow ceases to be so cold, when it has been standing in a room for some time. Finally one should find that both quantities of water behave in precisely the same way with respect to our sense of feeling. By further observations we find that heat and cold are different sensations which we experience through our sense of touch and they correspond, moreover, to the different states in which a body may be. This state of a body is called its temperature.