The first of thermometer

Thermometers were originally rather large devices, about a foot long and bent at a right angle, which had to be carried in a holster under the arm, much as ‘one might carry a gun’.

Prior to the 1620s there were a device called thermoscopiums, the modern term thermometer being first introduced around 1626. An Italian inventor name Santorio Santorio put number on it.

The Italian scientist Galileo is believed to have developed a primitive temperature measuring device around 1610, although it is possible that he experimented with such a device as early as 1592. It is the early water thermometer.

Galileo Galilei

The thermoscope was very sensitive to changes in temperature, but it was also affected changes in air pressure and this made it very inaccurate.

The French physicist Guillaume Amontons (1663-1705) improved on the design, but it was not until 1714 that the Polish-Dutch physicist invented the mercury thermometer.

In 1714, Daniel Fahrenheit invented the thermometer with Fahrenheit scale using mercury. On his scale, the freezing and boiling points of water are separated by 180 degrees.

The real breakthrough in thermometry was the development of reversing thermometers, first introduced in London by Negretti and Zambra in 1874.
The first of thermometer