Precursor Contributors to Meteorology (Renaissance [~1400 AD] through World War I)

Below are checklists of Precursor Contributors to Meteorology on postal items (stamps, souvenir sheets, aerogrammes, postal cards, etc.) and numismatic items (banknotes and coins). Catalog numbers, years of issue, and notes on the items featured are given when available. If readers know of additional information or images, please contact the authors using the e-mail addresses at the bottom of this page.

For (both chronological and alphabetical) lists of contributors to meteorology return to the Meteorologist Index page.

See also the following categories of Contributors to Meteorology:

• Ancient and pre-Renaissance Contributors to Meteorology (through 1300s AD)
• Modern Contributors to Meteorology (post World War I)

The following persons are presented in chronological order. See the bottom of this page for footnotes that are common to all of the tables below.

Sejong (King Sejong the Great of the Sejong Dynasty) (15th century)

King Sejong the Great of the Chosun Dynasty ruled Korea from 1418 to the mid-1400s. He sought to provide his subjects with adequate food and clothing through improvements in agriculture. Since droughts plagued the kingdom, he directed every village to measure the amount of rain that fell. This was done through the use of a rain gauge invented by his son, the crown prince Munjong, in 1441 (some 220 years before the European Christopher Wren invented his rain gauge). Munjong reasoned that instead of digging into the earth to attempt to measure rainfall, it would be preferable to use a standardized container. The design was probably based on gauges from much earlier times in China or India. King Sejong sent a rain gauge to every village, and they were used as the official tool to measure the harvest potential and determine the land taxes. This is one of the earliest documented cases of the development of an instrument designed to provide a quantitative estimate of a meteorological variable.

Cusanus (Nicholas of Cusa, Nicolas de Cues) (1401 - 1464)

Cusanus was a German cardinal, philosopher and administrator with interests in mathematics, astronomy and the physical sciences. He experimented with measuring the humidity of the air by weighing a piece of wool or a sponge when it was very dry, and again when it had absorbed moisture from the air. The idea for this procedure may have come from the classical Arab natural philosophers who had studied the physical sciences.

Alberti, Leon Battista (1404 - 1472)

Alberti was an Italian early Renaissance architect, artist and writer. In 1450, he invented the first mechanical anemometer. This instrument consisted of a swinging disk hanging vertically in calm conditions. In windy conditions, the disk would swing upward due to the force exerted on it by the wind. By the angle of inclination of the disk the wind force could be calculated, and in turn the wind speed estimated. The same type of anemometer was later re-invented by Leonardo da Vinci and Robert Hooke. This type of anemometer, generally referred to as a ‘swinging plate’ or 'deflection plate' anemometer, was used operationally by some countries as late as the mid-20th Century. It has now been superseded by the more accurate rotating cup anemometer.

da Vinci, Leonardo1 (1452 - 1519)

Da Vinci was a towering figure of Renaissance art and science. He invented the balance hygrometer some time in the period 1480-1486 (a hygrometer is a device used to measure atmospheric humidity). He also designed a deflection plate anemometer and an anemoscope (a type of wind vane). (Leon Battista Alberti was actually the first to design a deflection plate anemometer, in 1450). In da Vinci's notes for the anemometer, he mentions that one would “need a clock for ‘distance traversed per hour, with the force of the wind’ ”. With respect to his hygrometers, da Vinci made the comment that they could be modo a vedere quando si guasta il tempo (used for showing when the weather is breaking).

¹The drawing in red chalk (above) is widely (though not universally) accepted as an original self-portrait of da Vinci. However, the subject is apparently of a greater age than Leonardo ever achieved. But it is possible that he drew this picture of himself deliberately aged, specifically for Raphael's portrait of him in The School of Athens.

Paracelsus (Phillipus von Hohenheim) (1493 - 1541)

Paracelsus was a Swiss physician who studied the relationships between climate and weather and medicine. He wrote that anyone who studied winds, lightning and weather would understand what caused illness.

Nostradamus (Michel de Nostre Dame) (1503 - 1566)

Nostradamus was a French seer and visionary. He made many predictions of future events, but their real meaning is obscure and subject to interpretation. For example, when asked about tomorrow's weather, he wrote:

In the time of moons a man will be
A ponderer of cloud and raging storm.
Not for sake of probing philosophy,
But more because the cloudy brain's the norm.

From this we can interpret that he was critical of a preoccupation with the weather, and reluctant to make weather forecasts. Nevertheless, he was beset throughout his life by requests to "divine the skies," a task that he considered beneath him. The Queen of France was especially interested in his meteorological talents and begged him nightly to provide a forecast so that she would know "what to wear on the morrow". After a few of these forecasts, he finally refused, saying, "Flay me if you will, but I will not be seduced again into using my powers to predict your rainy day! Besides, would you not rather hear of the wonderful future of mankind than all this atmospheric gloom and doom"?

José de Acosta (1540 -1600)

Acosta was a Spanish Jesuit missionary and naturalist who served in South America. He studied earthquakes, volcanoes, tides, currents, magnetic declinations and meteorological phenomena. In his work Historia Natural y Moral de las Indias, published in 1590, he provided an explanation of the prevailing winds in the subtropical and middle latitudes. He attributed the regular easterly winds of the subtropics (the trade winds) to the movement of the heavens about a stationary Earth. According to his idea, part of this movement, transferred to the tropics, resulted in the trade winds. Acosta also attempted to explain the westerly or southwesterly prevailing winds of the mid-latitudes as being related to ascending or descending currents in the atmosphere. This idea has in it a hint of what is now known to be the atmospheric general circulation.

Brahe, Tycho (1546 - 1601)

Tycho Brahe was a Danish astronomer and astrologer who believed that the weather could be predicted through astronomical and astrological techniques.

As early as 1564, Brahe was working to provide an empirical basis for his astrometeorological ideas. In that year, he observed the heavens during the 12 days of Christmas to test his theory that the weather of the coming year could be forecast based on those observations. In his work De nova stella in 1573, he set his belief that the probable weather for each day could be predicted on the basis of heavenly configurations, and presented his principles for the production of astrometeorological almanacs. His theory attributed most weight to the Moon in varying the solar-controlled climate, on account of its proximity to the Earth. However, he warned readers not to expect too much from weather predictions, both because the motions and effects of the heavenly bodies had yet to be properly explored, and because the fluidity of sub-lunary matter could sometimes hasten events or delay them. He recommended that weather observations be kept so that prediction could be placed on a sounder footing in the future. In fact from 1October 1582 to 21 April 1597 he did just that: he kept a daily record of the weather in Hven, and in 1585 published, under the name of one of his students, an astrometeorological calendar for the coming year based on those observations. A few years later, in 1591, book based on his studies was published, also under the name of one of his students. It contained 399 aphorisms for weather prediction on the basis of the sky's appearance, the motions of the heavenly bodies, and the behaviour of animals (this approach is reminiscent of that of Theophrastus in his Book of Signs). Brahe's involvement in the book became clear when it was later revealed that he had composed its preface. Brahe continued to believe in astrological/astronomical weather prediction, although it become clear to others that local conditions influenced the weather much more than the heavens.

In his practical astronomical work, Brahe was aware that a star observed near the horizon appears with a greater altitude than the real one, due to atmospheric refraction, and he worked out tables for the correction of this error. He was in fact the first astronomer to make such corrections for atmospheric refraction. He also made observations of a comet and used a parallax method to show that it had to be outside the atmosphere. This conclusion went against Aristotle's idea of the immutability of the heavens.

Bacon, Francis (1561 - 1626)

Bacon was an English natural philosopher who believed that in the scientific arena one should touch and feel and measure things for oneself. As such, he was one of the earliest exponents of the scientific method, and so helped usher in a new era for science. Bacon had an insatiable curiosity about all natural phenomena. In his Preparative toward a Natural and Experimental History (written in 1620), he presented a large number of areas ("histories") in which he wished to "examine nature herself", including the following ones related to meteorology:

• History of lightnings, thunderbolts, thunders, coruscations;
• History of winds and sudden blasts and undulations of the air;
• History of rainbows;
• History of clouds, as they are seen above;
• History of the blue expanse, of twilight, of mock-suns, mock-moons, haloes, various colours of the Sun; and of every variety in the aspect of the heavens caused by the medium;
• History of showers, ordinary, stormy and prodigious; and also of waterspouts (as they are called) and the like;
• History of hail, snow, frost, hoar-frost, fog, dew and the like;
• History of all other things that fall or descend from above, and that are generated in the upper region;
• History of sounds in the upper region (if there be any), besides thunder;
• History of air as a whole, or in the configuration of the world;
• History of the seasons or temperatures of the year, as well according to the variations of Regions as according to accidents of Times and periods of Years; of floods, heats, droughts and the like.

Unfortunately there was just not enough time, and Bacon was not able to expound upon all these subjects. He did, however, manage to publish in 1622 his work Historia Ventorum (translated as The Natural and Experimental History of Winds).

Galileo Galilei (1564 - 1642)

Galileo was an Italian astronomer, mathematician, physicist and philosopher who was one of the pioneers of the modern scientific method. He believed that the laws of nature could be expressed in mathematics. This approach led Galileo to refute many of the conclusions that Aristotle had put forth in his work Meteorologica.

Galileo invented the thermoscope, a precursor to the thermometer, in around 1596. He wanted to measure hot and cold during the period he lived in Padua, Italy. His thermoscope consisted of a hollow glass bulb about the size of an egg, with a long thin glass neck open at its end. The bulb was heated with the hands, the unit was inverted and the neck opening submerged in a vessel containing water. When the hands were removed from the bulb, the water rose to a certain height in the neck above the level of the water in the vessel. This height depended on the temperature of the air: the colder the air, the higher the water would rise. There was no temperature scale on this instrument. Other inventors would later independently construct thermoscopes. The Italian inventor Santorio Santorio added a scale to his air thermoscope in about 1612.

Galileo coined the term Aurora Borealis (northern dawn) to describe the northern lights in or around 1619.

Near the end of his life, Galileo considered the problem of why water could not be pumped higher than 32 feet (10 metres) above the level of a reservoir. His student Torricelli continued this work, culminating in his invention of the mercury barometer in 1644.

See also the Galileo satellite page with images of the Galileo probe that was launched in 1989 and sent to explorer Jupiter and its moons from 1995 to 2003 when its mission ended.

Kepler, Johannes (1571 - 1630)

Kepler was a German astronomer and mathematician. In addition to his many other scientific works, he wrote one on snowflakes in 1611: A New Year's Gift, or The Six-Cornered Snowflake, in which he discussed the "reason for the six-angled shape of the snow crystals" (i.e. snowflakes) and "the forms and symmetries in nature". This work is the first known scientific reference to snowflakes and snow crystals.

Kepler believed that the weather patterns on the Earth were related to the geometrical relationships between the Earth and the planets. For example, he thought that the conjunction of Saturn and the Sun could produce cold weather. Since the positions of the Earth and the planets could be calculated in advance, then the weather could be as well. Kepler therefore made the first known long range weather forecasts, including one of a bitterly cold winter in Germany in 1593 which, it is said, turned out to be correct.

In 1593 Kepler began recording the daily weather in Graz, in the hope of clarifying the influence of the stars on the weather. He started similar observations in Prague in 1604. The Ephemerides Part II, for 1621 and 1629, contained Kepler's daily weather observations for 1617 to 1620. His calendars between 1617 and 1624 included weather predictions. He started another set of weather observations in Sagan in 1628.

Komensky, J.A. (Comenius) (1592 - 1670)

Komensky, also known as Comenius, was a Czechoslovakian philosopher, writer and educator. His work Opera Didactica Omnia included a discussion of weather-related topics.

Descartes, René (1596 - 1650)

Descartes was a French philosopher ("Cogito, ergo sum") and mathematician. In around 1631 he described an experiment to determine the atmospheric pressure, but did not build an apparatus to carry out the experiment. In Les Météores ("Meteorology", an essay published in his book Discours de la Méthode in 1637), he hypothesized that water vapour was a distinct substance in the air, composed of minute particles separated by a highly rarefied 'subtle matter'. In 1647, Descartes proposed that, in order to quantify the readings, a scale be attached to barometers of the type invented a few years previously by Torricelli. In that year, in letter to Marin Mersenne, he wrote:

"But, so that we may also know if changes of weather and of location make any difference to it, I am sending you a paper scale two and a half feet long, in which the third and fourth inches above two feet are divided into lines; and I am keeping an exactly similar one here, so that we may see whether our observations agree".

In this way, Descartes contributed to the development of the barometer.

Descartes was the first to separate white light into its component colours as it moved from one medium such as air to another such as glass. In Les Météores he discussed this refraction of light through his description of an experiment in which he found that the separated colours were arranged such that red always appeared at one side, and the blue or violet at the other. He used a ray tracing technique to explain the formation and structure of the rainbow. Newton would later add a theoretical explanation for the arrangement of the colours of the rainbow.

von Guericke, Otto (1602 - 1686)

Von Guericke was a German inventor, scientist and politician. Inspired by the work of Torricelli and Galileo, he proposed that air has weight and therefore must exert a pressure, and that both could be measured. To this end, he constructed a water barometer at about the same time and probably independently of Torricelli's invention of the mercury barometer in 1644. Outside his house, von Guericke erected a brass tube about 10 metres (35 feet) high with a transparent, sealed and evacuated glass portion at the top. This was his water barometer. At the top of the water inside the tube floated a small wooden mannequin which in fine weather rose with the water level due to rising atmospheric pressure to become visible through the glass. Conversely, in low pressure and bad weather it sank out of sight. Von Guericke attempted to make weather forecasts based on the information from his barometer.

While he was the mayor of Magdeburg (1646 - 1676), von Guericke continued to investigate air pressure and the properties of a vacuum. He invented a vacuum pump, and constructed what came to be known as Magdeburg hemispheres (two hollow copper hemispheres, each 51 cm in diameter, that could be held together to form a hollow sphere). In Magdeburg in 1654, he demonstrated that if the sphere composed of the two hemispheres were evacuated, then the pressure of the surrounding atmosphere would hold them together so strongly that teams of horses could not pull them apart. The demonstration was repeated in Berlin in 1663.

Von Guericke also experimented with the production of artificial clouds by releasing air from one flask into another from which the air had been evacuated. A fog then formed in the first flask, due to condensation related to the falling pressure in that flask. He concluded that air can not be turned into water, though moisture can enter the air and later be condensed back into liquid water. This line of reasoning followed from Descartes who had proposed in 1637 in his Discours de la Méthode that water vapour was a distinct substance in the air.

Torricelli, Evangelista (1608 - 1647)

Torricelli was an Italian mathematician. He was Galileo's most promising pupil, and succeeded him as professor of mathematics at Florence. His work Lezioni Accademiche (Florence, 1715), published nearly seventy years after his death, contains his lectures dealing with problems of mechanics, physics, meteorology and military architecture. The lectures on forces of impact and on the wind are of particular interest. In the former, he said that he was reporting ideas expressed by Galileo in their informal conversations. In the latter, Torricelli advanced the modern theory that winds are produced by differences of air temperature.

Near the end of his life, Galileo had considered the problem of why no pump, no matter how carefully contrived, was able to draw water from a well to a height of more than about 10 metres (33 feet) above the water level. Torricelli continued to work on this question. To this end, he and his student Vincenzo Viviani constructed a water barometer in 1643, but it was an inconvenient apparatus, requiring a very long (approximately 18 metres / 60 feet) and clumsy glass tube. By substituting mercury, which at room temperature is a liquid and about 14 times denser than water, Torricelli was able to reduce the length of the barometer tube to around 90 cm (35"). His instrument consisted of a long-necked glass tube with a closed bulbous end. The tube was filled with mercury and then inverted into a basin also filled with mercury. Rather than running completely out of the tube, the height of the mercury column fell to a level of about 76 cm (30") and then remained fairly steady, fluctuating by only a few per cent. We now know that these fluctuations were due partly to changes in temperature and partly to changes in atmospheric pressure above the instrument.

Torricelli was convinced by these results that the air above the barometer must have weight, and therefore must exert pressure, and that it was this pressure that was forcing the mercury to rise in the barometer tube. He also believed that the space above the mercury created by its descent from the bulb at the top of the tube must be a true vacuum.

Torricelli is generally credited with inventing the mercury barometer in 1644. However, his barometer had no scale, and so was useful for qualitative rather than quantitative measurements. René Descartes added a scale to the pressure tube barometer in 1647. It must also be noted that other people were working with similar concepts at about the same time. For example, the German Otto von Guericke, probably independently, invented a water barometer at about the same time that Torricelli was developing his own barometer.

Pascal, Blaise (1623 - 1662)

Pascal was a French scientist, mathematician and philosopher. One of his early interests was the study of fluids. This led him to design an experiment using a barometer like the one invented by Torricelli in 1644. In this experiment, carried out in 1648, the level of mercury in a barometer equipped with a scale was measured at the base of Puy-de-Dôme, and again at the top, some 1000 metres (3300 feet) higher (Descartes had attached the first such scale to Torricelli's barometer in 1647). The account of Pierre Florin, who carried out the experiment, records that the "quicksilver" reached a height of 26 inches plus 3 ½ lines at the base of the hill, compared to only 23 inches plus 2 lines at the top. This meant that the pressure exerted by the atmosphere decreased with height, consistent with the idea that the pressure was due to the weight of the atmosphere in the column above the barometer. Pascal later repeated the experiment in Paris, where he measured the pressure difference between the base and the top of a church bell tower.

To honour his scientific work with atmospheric pressure, Pascal's name was given to the SI (Système International) unit of pressure. One pascal is equal to one newton per square metre. Modern meteorologists often refer to atmospheric pressure in hPa (hectopascals). A typical sea level pressure would be around 1000 hPa. See the SI-metric unit names page for other persons after whom metric units were named.

In addition to the table below, another list of Pascal items is available on the SI-metric unit names page.

Cassini, Giovanni (1625 - 1712)

Giovanni Cassini was an Italian astronomer who spent much of his professional life in France. He knew that atmospheric refraction affected astronomical observations, and proposed a model to explain the refraction (though it later turned out to be incorrect). In 1683, with his colleague N. Fatio, he published a study that demonstrated that the phenomenon of zodiacal light has an astronomical rather than a meteorological source.

Cassini was also an expert in hydraulics and river management, and studied the flooding of the river Po.

The science satellite Cassini-Huygens, named after Cassini and astronomer Christian Huygens, was launched in 1997 and flew past Jupiter in 2000 on its way to Saturn. It provided the best images ever obtained of Jupiter, in which the planet's atmospheric circulation patterns are clearly seen.

Boyle, Robert (1627 - 1691)

Boyle was an Irish-born inventor and scientist who spent much of his life in England. He may have brought a Torricelli type of mercury barometer back to England after his studies in the Continent, and was one of the first to see the potential of the instrument for studying properities of the air. He built his own mercury barometers, and appears to have been the first to use the term 'barometer'. With Robert Hooke, he studied the physics of gases. After reading of Otto von Guericke's work with air pumps, Boyle and Hooke built an improved version, which Boyle used starting in 1659 to conduct a series of experiments on the properties of air. He published an account of this work, New Experiments: Physico-Mechanical Touching the Spring of Air and its Effects, in 1660. Boyle supervised the construction of the first sealed thermometer to be made in England, and his experiments with it were described in 1665 in his paper New experiments and observations touching cold, or an experimental history of cold.

Boyle is best known for his formulation around 1670 of a gas law generally referred to as Boyle's Law. It states that at constant temperature, the volume of an ideal gas is inversely proportional to the pressure. The real atmosphere, to a good approximation, follows this law. (In Europe, it is often attributed to E. Marriotte, who published it in 1676).

Huygens, Christian (1629 - 1695)

Huygens was a Dutch astronomer. His scientific bent led him to the conclusion that temperature measurements with thermometers would be useful only if they were made using a defined scale. (The first sealed liquid-in-glass thermometer was built in about 1654 by the Grand Duke of Tuscany, Ferdinand II. Santorio Santorio used a scale with his air thermoscope as early as 1612). Huygens proposed in 1665 a thermometer scale in which there would be two fixed points: the freezing and boiling points of water. The modern Celsius temperature scale can be traced back to this proposal. However, for many years after Huygens' time there was no agreement on a common scale, since several different ones were proposed, and used to different degrees (for more information, see the entries for Newton, Fahrenheit, Roemer, Celsius and Kelvin; no philatelic items for Ferdinand II and Santorio are known).

A scientific satellite known as Cassini-Huygens was launched in 1997, with the goal of studying Jupiter and Saturn. It arrived near Saturn in 2004, only a few months after Huygens' 375th birth anniversary, and its detachable probe (the part of the satellite that bore the name "Huygens") was launched into the atmosphere of Titan to make measurements there.

Wren, Christopher (1632 - 1723)

Wren was an English mathematician, astronomer and architect who had a wide variety of scientific interests, including meteorology. While studying at Oxford in around 1650, he produced preliminary designs for a rain gauge and an automatic weather observing station. In the 1660s and 1670s he experimented with a swinging plate anemometer of the type invented by Alberti in 1450; an instrument to measure humidity; "weather glasses" (small open water barometers); and Torricelli type mercury barometers. In the early 1660s, probably in collaboration with Robert Hooke, he also constructed a tipping bucket rain gauge for recording rainfall amounts. This was the earliest English rain gauge, and the first recording rain gauge ever constructed. Benedetto Castelli had devised the first (non-recording) European rain gauge in Italy in 1639, and earlier rain gauges date from the mid-14th century in Korea, in the reign of King Sejong, and from much earlier still in China and India.

Wren continued to refine his idea of an apparatus that he called a "weather clock" that would automatically record the weather, and in December 1663 described his concept to the Royal Society in a paper entitled Description of a weather clock. Hooke immediately siezed upon the idea and proposed some improvements. The two continued to work together on the design, culminating in the first working model, known as the "weather wiser", constructed by Hooke in 1669. It is interesting to note that Wren's idea of automatic weather recording skipped entirely the idea that human observers might act to regularly observe and record the weather.

Wren realized that weather observations could potentially be used to predict the weather, and in 1679 presented to the Royal Society a possible method for doing this.

Wren also saw a relationship between medicine and meteorology through the idea that there were certain "epidemic seasons" that could be identified. This is reminsicent of the ideas of Galen and Hippocrates who believed that certain climate and environmental conditions were one cause of diseases.

Hooke, Robert (1635 - 1703)

Hooke was an English experimental scientist and instrument maker. He worked in a wide variety of areas, including meteorology. Early in his career, Hooke collaborated with Robert Boyle in studies of the properties of gases and in experiments with barometers. Hooke was the first to observe sunspots through the use of the helioscope he designed for studying the sun. He conducted experiments to weigh air and water vapour in 1663-4 and reported on them in his paper Account of experiments concerning the weight of the air & proportion of the weight of air to that of water. He considered the need for scales for thermometers to obtain consistent temperature values. To this end, he proposed that the freezing point of water would serve well for the zero point, but seems not to have considered the need for a second fixed point. Newton and others would later add a second fixed point to their temperature scales.

Starting in 1662, Hooke worked during 40 years as the curator of experiments for the Royal Society of London. In the 1660s and 1670s, he invented or improved upon several meteorological instruments. Much of this work was done in collaboration with his friend Christopher Wren.

Hooke developed the 'wheel barometer', which was a Torricelli type mercury barometer with a mechanical linkage designed by Hooke to magnify small changes in the level of the mercury. These changes were displayed through the motion of a dial on the 'wheel'. This type of barometer was common long after Hooke's time. The weather-related legends such as "fair", "unsettled" and "rain" that were eventually added to the wheel have survived to this day.

Hooke refined the swinging-plate anemometer of the type invented by Alberti in 1450. This design was the most commonly-used anemometer for some 200 years after Hooke's time, and later versions were used through the mid-20th Century in the USSR and Soviet bloc countries. Furthermore, in The posthumous works of Robert Hooke, M.D.S.R.S. Containing his Cutlerian Lecture and other discourses (edited by R. Waller, published by Sam Smith and Beni Walford, London, 1705) it is noted that on 14 November 1683 "Mr Hooke shew'd an instrument to measure the velocity of the air or wind and find the strength thereof which was by four vanes put upon an axis and made very light and easy for motion; and the vanes so contrived as that they could be set to what slope should be desired". Clearly, Hooke was close to the idea of the modern four cup anemometer, which was finally developed only in 1846 by Dr. John Robinson

Hooke constructed the first practical hygrometer for humidity measurements, based on his observation that the hairs from a goat's beard would bend when dry and straighten out when wet.

In 1663 Hooke presented to the Royal Society a paper entitled A method for making the history of the weather. It contained a comprehensive set of instructions for making weather observations, and also Hooke's recommendation that a national or international network of stations be established for the purpose of making weather observations to a common standard with calibrated instruments. These were yet more ideas that were far ahead of his time: the earliest networks of stations performing regular weather observations were set up in some European countries in approximately the mid-1850s.

In around 1669, Hooke presented to the Royal Society a working version of Wren's weather clock, known as the "weather wiser". Wren had presented his design to the Society in 1663, and Hooke had promptly improved upon it. Hooke and Wren continued to develop the apparatus together, though Hooke did the actual construction. The weather wiser incorporated Wren's tipping bucket rain gauge, and used trip hammers to mark the paper on a rotating drum with continuous measurements of pressure, temperature, rainfall, humidity, wind speed and wind direction. This was in fact the world's first automatic weather observing station. As a complicated mechanical apparatus, it was probably in need of constant repairs, but the concept of such a device as well as its construction was certainly revolutionary and far ahead of the times.

Hooke was also interested in practical aspects of the weather, and argued that hurricanes, storms, mists and fogs were all effects associated with 'denser air'. He also made detailed drawings of snowflakes and hailstones.

Hooke realised that if daily meteorological readings were tabulated, it might then be possible to use them to forecast the weather, especially if the readings were available from a number of stations in a network. His friend and colleague Wren presented a possible method for doing this to the Royal Society in 1679.

For all his meteorological work, and particularly for his development of meteorological instrumentation and his prescient recommendation that regular weather observations should be made to common standards in a network of observing stations, Hooke has been called the 'father of scientific meteorology'.

Newton, Isaac (16421 - 1727)

Newton was an English physicist and mathematician who made many important scientific discoveries. In the area of temperature measurement, he considered how thermometers could provide standard, reproducible values, and adopted Huygens' idea of a temperature scale defined by two fixed values. Huygens had suggested the freezing and boiling points of water as the two reference values. Newton kept the freezing point as his lower fixed value, but suggested that the upper reference be equal to the human body temperature. He then divided the range between the two reference values into 12 equal segments (so the body temperature would be equal to 12 degrees on this scale). Newton extrapolated the scale to warmer temperatures and found that its value for the boiling point of water would be about 33 degrees. He put forth these ideas in around 1701. Roemer and Fahrenheit would later build on this approach. It is interesting to note that Newton's scale corresponds closely to the modern Celsius temperature scale in the following way: if we multiply Newton's reference values by 3, then we retain 0° (3 X 0) for the freezing point of water (0°C), and obtain 36° (3 X 12) for the normal human body temperature (actually 37°C) and 99° (3 X 33) for the boiling point of water (actually 100°C).

Newton studied the properties of light, and confirmed Descartes' observation that white light would be separated into its constituent colours through the process of refraction. He then developed a theory to explain the colours, and showed in his work Opticks, published in 1704, that his theory explained the arrangement of colours observed in a rainbow.

In addition to the table below, another list of Newton items is available on the SI-metric unit names page.

See also the X-ray Multi-mirror Mission (XMM) / Newton satellite page with images of the astronomy satellite that was launched in 1999.

¹Isaac Newton was born on 25 December 1642 on the Julian Calendar. On the Gregorian Calendar, Newton's birth occurred 4 January 1643.

Roemer, Olaus (Rømer, Ole) (1644 - 1710)

Roemer was a Danish astronomer. In the early 1690s, he began to measure and record the air temperature to account for its effects on his astronomical work, and starting in 1702 he constructed his own spirit (alcohol) thermometers. He also devised a temperature scale to use with them, in which the freezing point of water was 7.5 degrees and its boiling point was 60 degrees. In this scale, 0°Rø would have been equal to the modern -22.5°C. This is in qualitative agreement with Roemer's measurements made with his scale during the very cold winter of 1709.

In 1708 Daniel Fahrenheit, a young scientist eager to learn about Roemer's work, visited him in Copenhagen. Roemer showed him a modified scale, with the upper fixed point of 22.5°Rø being the human body temperature (which he supposed constant), while the lower fixed point of 7.5°Rø was unchanged from his earlier work. Newton in 1701 had used the same two fixed points in his suggested temperature scale. Fahrenheit would later modify Roemer's scale. Still later modifications after Fahrenheit's death led to the temperature scale still used in the US, which can therefore be traced back to Roemer.

Leibniz, Gottfried Wilhelm (1646 - 1716)

Leibniz was a German mathematician. In a letter written in 1702 to Jacob Bernoulli (whose uncle Daniel Bernoulli did pioneering work in fluid dynamics), Leibniz was the first to propose how a non-liquid aneroid barometer would work: he suggested that an aneroid barometer would use "a small closed bellows which would be compressed and dilated by itself as the weight of the air increases or decreases". He first thought that the bellows should be made of leather, but later suggested using metal instead. However, he could find no one who could manufacture the apparatus, and never did construct a prototype himself. (Lucien Vidie built the first working aneroid barometer in France around 1844, but no philatelic items are known that mention him.)

Halley, Edmund (1656 - 1742)

Halley was an English astronomer who studied comets and for whom Halley's Comet was named. His many other scientific interests included meteorology and the Earth's magnetism.

As early as 1678 Halley attempted to describe the general circulation of the air, with emphasis on the trade winds and the monsoons, and to relate them to differential solar heating over the Earth. Modern ideas of how the distribution of solar heating controls the atmospheric general circulation can therefore be traced back to Halley.

In 1686, Halley established for the first time a mathematical relationship between barometric pressure and height above sea level.

Also in 1686 he drew what is considered to be the first meteorological chart. It was a map of a large part of the world showing the trade winds and the monsoon winds in a way that, as he explained, "may be better understood than by any verbal description whatsoever" (An Historical Account of the Trade Winds, and Monsoons, Observable in the Seas Between and Near the Tropicks; With an Attempt to Assign the Phisical Cause of Said Winds, Philosophical Transactions, vol. 183 (1686), pp. 153-168). In his chart, the winds were symbolized by "the sharp end of each little stroak pointing out that part of the Horizon whence the wind continually comes; and where there are Monsoons the rows of stroaks run alternately backwards and forwards, by which means they are thicker [i.e. denser] than elsewhere".

Halley conducted some experiments to measure evaporation at the headquarters of the Royal Society of London, and used those measurements along with his estimates of the flow of the Thames to estimate the flow of rivers into the Mediterranean and the evaporation from the Mediterranean. This is a very early example of a scientific hydrological study.

In 1700 Halley realized that values of magnetic declination could be displayed as contour lines on a map, and produced the first such map over the area stretching from Europe and Africa westward to the Americas. He was also interested in the aurora, and in 1716 suggested that "the aurorae are caused by 'magnetic effluvia' moving along the Earth's magnetic field lines". In other words, he postulated that auroral curtains are aligned with projections of the Earth's magnetic field into the upper atmosphere (An Account of the late Surprising Appearance of the Lights seen in the Air, on the sixth of March last: with an Attempt to explain the Principal Phaenomena thereof, Philosophical Transactions (1683-1775), vol. 29 (1714 - 1716), pp. 406-428).

Halley's Comet items have been excluded from the table below, unless they specifically show Edmund Halley. Many of those Halley's Comet items are available on the Giotto, Planet, and Vega satellite pages.

Fahrenheit, Daniel Gabriel (1686 - 1736)

Farenheit was a German instrument maker who spent much of his working life in Holland. The young Fahrenheit was fascinated with instruments. He travelled through Europe and studied with various scientists and craftsmen. He spent a few years in London, where he became a member of the Royal Society and contributed papers to the Society on temperature, anemoscopes and barometers.

In 1708 he visited Roemer in Copenhagen. Roemer showed him his temperature scale, which had an upper fixed of point of 22.5°Rø (the human body temperature, supposed constant) and a lower fixed point of 7.5°Rø (the freezing point of water). Fahrenheit, no fan of "inconvenient and awkward fractions" according to his letters, modified Roemer's scale. He divided each degree into four parts, so that the lower fixed point became 30° (4 X 7.5) and the upper fixed point became 90° (4 X 22.5). On this scale the boiling point of water is 205°. He used this modified Roemer scale until around 1717 when he decided to make small changes to the fixed points, so that the freezing point of water became 32°F and the human body temperature became 96°F. On this changed scale the boiling point of water was 212°F. Fahrenheit made this change for a very practical reason. With fixed points of 32° and 96°, there were 64 degrees between the two, and a scale with 64 divisions could easily be drawn by successive subdivisions of the full interval into two equal parts, since 64 is a power of two. This procedure is not possible if the fixed points are 30° and 90°. Later when he discovered that the human body temperature is not constant (e.g. young people tend to have a higher body temperature than their elders), Fahrenheit simply redefined the upper fixed point as being equal to the boiling point of water, with the value of 212°F.

Fahrenheit is generally credited as the first person to make commercially-available reliable thermometers. His originally followed common practice and used alcohol in his thermometers, starting in around 1709. However, he was able to develop a method to purify mercury, and so in 1714 became the first person to take advantage of its properties for use in thermometers. Another of his improvements to thermometer design was the introduction of cylindrical bulbs to replace spherical ones. Fahrenheit seems to have been a good businessman, and his detailed technique for making thermometers remained a trade secret for some time. Perhaps the commercial availability and quality of his thermometers explain why his temperature scale became so widely accepted, while other scales remained in obscurity.

Among the other instruments which he devised were a constant-weight hydrometer and a "thermobarometer" designed to estimate barometric pressure by determining the boiling point of water.

The United States is now the only major country that still clings to the Fahrenheit temperature scale. The vast majority of the rest of the world uses the Celsius temperature scale, which is the accepted international standard for temperature measurement.

The table below includes only items with the name Fahrenheit spelled out. Many o