Newton Scale (°N)

One of the earliest numbered temperature scales, devised by Isaac Newton around 1700 using linseed oil as the working fluid.

Newton described his scale in an anonymous paper of 1701, setting the freezing point of water at zero and its boiling point at 33. He used linseed oil rather than mercury because it expanded more readily, and calibrated intermediate points against melting wax, glowing coals and the heat of the human body. The scale never achieved wide adoption, but it established the principle of assigning reproducible numbers to degrees of heat.