Lectures on Thermodynamics - Introduction: The Principles of Thermodynamics #263541

One of the most fundamental concepts employed in the study of physical phenomena 'is the concept of the tempera ture* of a body. We distinguish, through touch, between 'hot' and 'cold' bodies. A block of ice feels 'cold' the air in the evening feels 'cool'; a cup of tea feels 'lukewarm'; We boil it, and it feels hot.' We thus establish a qualitative scale of the degrees of hotness or 'temperatures' of bodies.