Guillaume Amontons, 1663 – 1705, French scientific instrument inventor and physicist.
The Principles of Static and Friction. The principles being described come from two noted scientists: Guillaume Amontons (1663-1705) and Bernard Forest de Bélidor (1697/98-1761).
The Principles of Static and Friction. The principles being described come from two noted scientists: Guillaume Amontons (1663-1705).
While still young, Guillaume lost his hearing, which may have motivated him to focus entirely on science. He never attended a university, but, after vain efforts to develop a perpetual motion machine, he decided, despite his family’s opposition, to study physical sciences and mathematics. He also spent time studying the skills of drawing, surveying, and architecture.
After studying drawing, surveying, and architecture, Amontons was employed on various public works projects that gave him practical knowledge of applied mechanics. Later he studied celestial mechanics and applied himself to the improvement of hygrometers, barometers, and thermometers.
His first scientific production was a hygrometer in 1687. The apparatus consisted of a ball of beechwood, horn, or leather filled with mercury; it varied in size according to the humidity of the atmosphere. In 1688 he developed his shortened barometer, composed of several parallel tubes connected alternately at the top and bottom, with only alternate tubes containing mercury.
Sometime between 1688 and 1695, Amontons tried out his optical telegraph in the presence of the royal family. He published no data on this experiment, but the device is known to have consisted of a series of stations, each equipped with a spyglass, for the rapid transmission of signals. The nature of the signals to be transmitted is not known, however.
In 1695 Amontons sought to renew the use of the clepsydra as a timing apparatus on ships in order to solve the problem of determining longitude at sea. In his paper on this, he described two apparatuses that became well known by his name in the eighteenth century, although their use was never common. One was a cisternless barometer consisting of a tube narrow enough for the column of mercury to remain suspended. In his experiments with this, Amontons gradually broadened the tube into the shape of an inverted funnel. The mercury column then became shortened as atmospheric pressure decreased and lengthened as it increased.
The other was an air thermometer independent of the atmospheric pressure. Air occupied the top of one of the branches of a U-shaped tube, and by its dilation it pushed down one of the mercury columns so that the other end of the branch formed a barometric chamber.
As early as 1699 Amontons proposed a thermic motor: a machine using hot air and external combustion with direct rotation. The experiments carried on in connection with this machine led him to note that ordinary air going from the temperature of ice to that of boiling water increases its volume by about one third.
In the same year Amontons produced the first known study on the question of losses caused by friction in machines. He then established the laws of proportionality between the friction and the mutual pressure of the bodies in contact.
In 1702 Amontons returned to thermometry. Having noted that water ceases to increase its temperature from the boiling point, he proposed that the latter be the fixed thermometric point. He also observed that for an equal elevation of temperature, the increase of pressure of a gas always exists in the same proportion, no matter what the initial pressure.
The following year Amontons indicated practical ways of graduating ordinary alcohol thermometers. Also, returning to his observations of 1702, he proposed an explanation for certain natural catastrophes, such as earthquakes: If there is air very deep within the earth, it is extremely compressed and could reach an irresistible pressure as the result of a relatively small increase in temperature.
Among Amonton’s last works was a barometer with a U-tube, without an open surface of mercury, to be used on shipboard. Using the same receptacle and liquids whose coefficients of expansion differed, Amontons was able to establish as false the theory that liquids “condense and cool first, before expanding with approaching heat.” The observed results were due only to the expansion of the containers. Also, using a barometer as an altimeter, he tried to verify the exactitude of Mariolte’s (Boyle’s) law at low pressures.
One really cannot understand what has led certain authors to attribute to Amontons the creation of an air thermometer of unvarying volume. As for the idea of absolute zero, he barely implies it in his memoir of 1703 (“Le thermomètre réduit à une mesure fixe,” pp. 52-54); this brief notice nevertheless presented Johann Heinrich Lambert with a point of departure for his explication of this idea (1779).
Guillaume Amontons died on October 11, 1705 in Paris, France.
Amontons was a Member of Académie des Sciences (1690).
As a boy, Guillaume Amontons became almost deaf during adolescence.
Quotes from others about the person
"When a [mercury] thermometer … was made (perhaps imperfect in many ways) the result answered to my prayer, and with great pleasure of mind I observed the truth (that water boils at a fixed degree of heat)."— Gabriel Fahrenheit
"I read … that the celebrated Amontons, using a thermometer of his own invention, had discovered that water boils at a fixed degree of heat. I was at once inflamed with a great desire to make for myself a thermometer of the same sort, so that I might with my own eyes perceive this beautiful phenomenon of nature." — Gabriel Fahrenheit
"It then came into my mind what that most careful observer of natural phenomena [Amontons] had written about the correction of the barometer; for he had observed that the height of the column of mercury in the barometer was a little (though sensibly enough) altered by the varying temperature of the mercury. From this I gathered that a thermometer might be perhaps constructed with mercury." — Gabriel Fahrenheit