In 1593, Galileo measured room temperature using a glass cylinder containing alcohol the density of which increased considerably when the temperature decreased. Glass balls of various densities with numbered tags attached to them floated in the liquid which rose or fell as the alcohol became more or less dense. The scientists of the Cimento Academy in Florence made two different kinds of thermometers and published their experiences with heat in a book. To tell the truth, rather than measuring temperatures, these thermometers only indicated variations. Thermometers were still calibrated experimentally and the various scales could not be compared. The comparable thermometer was produced later on the basis of certain fixed starting or finishing points (the temperatures of boiling water and melting ice). This led to three fundamental scales: Celsius, Réaumur, Fahrenheit and mercury was chosen as the basic substance.

Our pewter indoor/outdoor thermometers are marked with two or three fundamental scales: Celsius, Fahrenheit and Réaumur. On some articles we have patented a method that makes use of a rotating partition to make it easier to read one scale rather than another. The "minimum and maximum" thermometer features a special marker that measures the minimum and maximum temperature of a day, month or year.