Guillaume Amontons, Deaf French Scientist and Inventor

Have you ever seen the trick of putting an egg inside a bottle without breaking it? Have you ever seen when a half-empty plastic bottle compresses with the change of temperature? A deaf French scientist and inventor born more than 350 years ago explained why this happens in addition to other important scientific discoveries and inventions.

Guillaume Amontons muestra el semáforo en los Jardines de Luxemburgo
Illustration by Guillaume Amontons in 1690 showing one of his inventions in 1690 (1870 illustration by Hulton Archive)

Passion For Science

Guillaume Amontons was born in Paris in 1663. The son of a lawyer, his deafness was caused by a serious illness during his childhood and he enjoyed building scientific apparatus instead of toys like other children. Soon, during his youth, he became passionate about the instruments used in physical experiments.

Intuitive and Great Inventor

At the age of 24 he invented a hygrometer, a device to measure the degree of humidity in the air, and presented it to the French Academy of Sciences. His dream was to belong to this Academy and he finally achieved it at the age of 36, when he formulated three important laws of friction that are now studied in any physics manual:
1. The force of friction is directly proportional to the applied load. 2. The force of friction is independent of the apparent area of contact. 3. Kinetic friction is independent of the sliding velocity.
His last great invention was made just before he died, in 1705, creating the air thermometer, a barometer, an instrument used to measure air pressure, which is fundamental in navigation, aviation or mountaineering. The great novelty of his barometer is that it did not have mercury or alcohol like all the barometers known up to that time.

Guillaume Amontons
Guillaume Amontons

Amontons also had great intuition: he is credited with being the first person to consider the temperature of absolute zero, long studied by science in the following centuries, and he is acknowledged to have been the first person to work on an optical telegraph although he did not finally obtain the financial support to build it. In his mind he had the idea that it could be used by deaf people, since the traditional telegraph was not accessible. The optical telegraph works like this:
It is a system using a line of stations, typically towers, for the purpose of conveying textual information by means of visual signals. There are two main types of such systems; the semaphore telegraph which uses pivoted indicator arms and conveys information according to the direction the indicators point, and the shutter telegraph which uses panels that can be rotated to block or pass the light from the sky behind to convey information. (Wikipedia).
In the following video you can see the functioning of the optical telegraph, also called 'semaphore' (from minute 1:18, optional subtitles in English):

Amontons is probably the only deaf scientist who joined the French Academy of Sciences. Far from complaining about his deafness, Amontons never went to a doctor and said he was grateful that his deafness allowed him to concentrate on his scientific work without distractions.

A crater discovered on the moon caused by some impact was named in his honor, so it is known as the Crater of Amontons.

Fun Science Thanks to Amontons

Guillaume Amontons' studies explain some fun science experiments. One of the best known is how to introduce an egg into a bottle, which is achieved thanks to the pressure of the hot air inside it. In the following educational video aimed at children and young people he explains it very well (with closed captions in English):

Another well-known experiment is that of a plastic bottle that is compressed. This can be seen daily when a plastic bottle is left closed with water and different temperature from the outside, but these students show the Law of Amontons in a video (without subtitles):


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