Temperature feels inevitable today. In the 1700s it was anything but: instrument makers and scientists were still deciding what reference points and numbers should mean.
Early instruments could show that something was warmer or colder without assigning a universal number. Reproducible fixed points and standardized scales changed that.
Ole Rømer used reproducible reference points including a saltwater mixture; Isaac Newton also experimented with fixed temperature points. Their work helped turn thermoscopes into quantitative thermometers.
Fahrenheit, a Polish-born instrument maker who worked in the Netherlands, was influenced by Rømer and became known for highly reproducible mercury thermometers. His scale initially used a brine freezing point near zero and a human-body reference near 96; later standardization fixed water at 32 °F freezing and 212 °F boiling under standard conditions.
A historical account of Anders Celsius's work identifies Christmas Day 1741 as the first recorded use of his own 100-point scale at the Uppsala observatory.
Celsius defined two reproducible water points separated into 100 degrees, but his original orientation placed 0 at the boiling point and 100 at the freezing point.
In Lyon, Christin reversed the centigrade direction so that water froze at 0 and boiled at 100. That orientation became the familiar modern arrangement.
The future Lord Kelvin published On an Absolute Thermometric Scale, placing zero at the physical lower limit of temperature rather than at an arbitrary water reference.
The International Committee for Weights and Measures chose “degree Celsius” from competing names, and the 9th General Conference on Weights and Measures adopted it as well.
Version 1.0 formally established the Galliera scale on 18 August 2026 with TG = 2TC. Version 1.1, issued 21 August 2026, preserved that definition and made the whole-number granularity comparison with Celsius and Fahrenheit explicit.
Daniel Gabriel Fahrenheit (1686–1736) was born in Danzig (now Gdańsk) and worked as a scientific instrument maker in the Netherlands. He became a Fellow of the Royal Society in 1724.
The achievement was not merely choosing numbers. Fahrenheit's mercury thermometers were reproducible enough that measurements made on different instruments could agree far better than many earlier devices.
The familiar modern water points are 32 °F for freezing and 212 °F for boiling at standard atmospheric pressure, giving 180 Fahrenheit degrees between them. Earlier versions of Fahrenheit's calibration used other fixed points, including a saltwater mixture and human body temperature.
Anders Celsius (1701–1744) was a Swedish astronomer and professor at Uppsala University. He had been comparing thermometers and weather observations for years before proposing his own scale.
In Celsius's 1742 scheme, boiling water was 0 and freezing water was 100. This sounds strange today, but it was not unique: other early scales also ran in directions modern users would find counterintuitive.
The enduring contribution was the use of two reproducible water reference points divided into 100 equal intervals, together with careful attention to pressure effects on boiling.
Kelvin solved a different problem. Instead of picking a convenient everyday zero, it anchors the scale at absolute zero. Its interval size is the same as Celsius.
0 K is the physical lower limit of thermodynamic temperature. It corresponds to −273.15 °C and therefore −546.30 °G.
The SI unit is the kelvin, symbol K, not “degree Kelvin.”
Galliera is explicitly not proposed as a substitute for Kelvin in thermodynamics or metrology.
The historical page uses institutional and scholarly sources rather than repeating internet folklore.