da Vinci, Leonardo (1452 - 1519)		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.

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 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.

Theophrastus Philippus Aureolus Bombastus 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 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.

See also the Kepler satellite on the astronomical/telescope satellites page. The Kepler satellite is a NASA space telescope whose mission is to discover Earth-like planets near other stars.

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 (International System of Units) 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.

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 scientific 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).

In the years before Boyle's death in 1691, John Locke was engaged in editing the manuscript of Boyle's General History of the Air. This pioneering meteorological work included Locke's weather observations for the period 1666 through 1683 as well as those of several other observers. The book was published posthumously early in 1693.

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).

The scientific satellite Cassini-Huygens, named after Huygens and astronomer Giovanni Cassini, 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.

Locke, John (1632 - 1704)

Locke was an English physician and philosopher. He was a friend of Robert Boyle, who urged him to keep a weather diary or weather journal following a trend that originated in the Royal Society in the 1660s. Robert Hooke also encouraged this type of activity and published a comprehensive set of instructions for making weather observations in his paper 'A Method for Making a History of the Weather'. It was presented to the Royal Society in around 1663. Locke started his own weather journal in 1666 and continued to fill it out, though with some gaps, until 1703. He generally approached the activity with enthusiasm, since he believed that the regular collection of meteorological data would contribute to the understanding of weather patterns. For example, during the first 6 months of his residency in Oxford, he managed to record almost every day at least two readings of his thermometer, barometer and wind gauge. Boyle cited some of Locke's data in the article in which he coined the term 'barometer'.

In the years before Boyle's death in 1691, Locke was engaged in editing the manuscript of Boyle's General History of the Air. This pioneering meteorological work included Locke's weather observations for the period 1666 through 1683 as well as those of several other observers. The book was published posthumously early in 1693.

While living in Essex, Locke continued to read his instruments and record the observations at least once a day from 1691 to 1703.

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.

To honour his scientific work, Newton's name was given to the SI (International System of Units) unit of force. One newton is equal to one kilogram metre per second squared. See the SI-metric unit names page for other persons after whom metric units were named.

See also the X-ray Multi-mirror Mission (XMM) / Newton 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 U.S., 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, 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), 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.

Bering, Vitus (1681 - 1741)

Bering was a Danish navigator and explorer who headed a number of Russian expeditions to Siberia from 1733 through 1739. They were carried out under the direction of the St. Petersburg Academy of Sciences. Following the instructions of the Academy, Bering and the other expedition leaders measured temperature and barometric pressure and made non-instrumental measurements of clouds, thunderstorms and other weather and natural phenomena. Many decades later, in the years 1804 to 1806, Lewis and Clark would make similar weather observations during their expedition across the western USA.

Bering's expeditions also set up some of the earliest observing stations in Siberia, but they operated only through around the mid-1700s. A sustained network of Russian weather observing stations was set up only in the 1830s, following the work of Adolpf Kupfer and Alexander von Humboldt.

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 latter instrument is now known as the 'hypsometer' or 'hypsometric thermometer'. Fahrenheit is credited with the earliest invention of this instrument (in 1724). Around 1800 de Caldas independently re-invented it.

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 other items, indicated only by the symbol °F for degrees Fahrenheit are available on the thermometers, temperatures and temperature units page.

Diviš, Prokop (1698 - 1765)

Diviš was a Czechoslovakian thelogian who experimented with atmospheric electricity. He has been called the "European Franklin". He attempted to draw electricity from clouds and built a functional lightning conductor (lightning rod) at about the same time as Benjamin Franklin, but his work may not have been done completely independently of Franklin's work, which was already known in Europe in the early 1750s. (For example, in May of 1752 in France, Thomas François d'Alibard conducted an experiment similar to Franklin's.)

In any case, a grounded lightning rod was erected by Diviš at Prenditz, Moravia in 1754. This was the first practical European lightning rod. Diviš petitioned the Emperor Franz-Josef in1755 to put up similar rods all over the country and thus protect the land from lightning, but the proposal was rejected on the advice of the mathematicians of Vienna. The lightning rod at Prenditz remained standing for 6 years, until it was torn down by an angry mob convinced that it had caused a drought.

Bernoulli, Daniel (1700 - 1782)

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Country	Catalog Number*	Type of Item**	Year of Issue	Notes on Content***
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Celsius, Anders (1701 - 1744)

Celsius was a Swedish astronomer and mathematician who worked in thermometry and studied the Aurora Borealis.

Around 1701 Newton had proposed a temperature scale in which the lower fixed point was 0° and the upper fixed point was 12°. On this scale the boiling point of water was 33°. Celsius was probably aware of this work and built on it in 1742 by proposing a 100 degree scale between the freezing point of water (100° in his original scale) and the boiling point of water (0° in his original scale). He published this proposal in a paper entitled Observations on two persistent degrees on a thermometer. It is not known what led him to associate the higher value with the colder fixed point, and vice versa. Perhaps he wanted to introduce more originality into his work, or perhaps he was influenced by the Royal Society's temperature scale (used until about 1725), in which the '0' was 'extreme hot' and '90' was extreme cold.

In any case, Celsius' proposed scale was intuitively backwards and was inverted soon after his death so that 0° was the lower fixed point and 100° the upper fixed point. In this way the modern Celsius scale was born. It was accepted as a standard, first in Sweden and France, and then across the globe. Temperature values measured in this scale were originally referred to as degrees "centigrade" ('centi' referring to one hundred, and 'grade' referring to degrees). However, in 1948 Celsius' name became the official temperature unit, when the Ninth General Conference of Weights and Measures declared that 'degrees centigrade' should thereafter be referred to as 'degrees Celsius'. In the early 21st century, only the United States still clings to the Fahrenheit scale; the Celsius scale is the accepted international standard everywhere else.

Celsius was also interested in the Aurora Borealis. In 1724 he and his student Olaf Peter Hiorter noted that the aurora borealis are accompanied by deflections of a magnetic compass. This discovery confirmed the relationship between auroras and magnetic fields. Celsius' observations of the aurora were published in Nuremburg, Germany in 1733 in a work entitled Observations of the Northern Lights in Sweden.

In addition to the table below, another list of Celsius items is available on the SI-metric unit names page. For a single temperature-related item listed below (from Ghana), the name Celsius is spelled out. Many other items, indicated only by the symbol °C for degrees Celsius are available on the thermometers, temperatures and temperature units page.

Franklin, Benjamin (1706 - 1790)

"Some are weather-wise, some are otherwise!" This quip is attributed to Benjamin Franklin, one of the founding fathers of the United States. He was not only a political pioneer, but also a scientist with a keen interest in the weather. His work in atmospheric electricity led to his becoming the first American with an international scientific reputation. The body of his weather-related work represents a major 18th century contribution to the science of meteorology.

In Philadelphia, Franklin attempted to observe a lunar eclipse on 21 October 1743, but clouds that arrived from the southwest ahead of a storm covered the sky and hid the eclipse. This happened despite winds near the surface that were blowing from the northeast. Franklin noted this difference, and later learned from his brother that clouds from the same storm had not reached Boston until after the eclipse. Boston is to the northeast of Philadelphia, and Frankin concluded that the storm as a whole must have been moving toward the northeast, despite the fact that the winds near the surface were from the northeast. This is the first recorded instance in which a scientist realized that the movement of a storm as a whole could differ from the motion of the air at the surface.

In 1749 Franklin observed updrafts of air, and concluded that they were due to local heating of the surface by the sun. He was one of the first to present this explanation for this phenomenon. Such updrafts lead to the summertime clouds now known as convective clouds.

Franklin was interested in the Gulf Stream: the temperature of its waters, and their direction and speed of flow, and in fact published the first known map of the Gulf Stream.

Franklin also studied waterspouts. In his paper Waterspouts and Whirlwinds he included a diagram of showing his hypothesized structure of a waterspout (the diagram is reproduced on U.S. Scott 4022, which is found in the table below). Concerning their formation, he wrote that:

"The air immediately over it [the Gulf Stream], however, may receive so much warmth from it as to be rarified and rise, being rendered lighter than the air on each side of the stream; hence those airs must flow in to supply the place of the rising warm air, and meeting with each other, form those tornados and waterspouts frequently met with, and seen near and over the stream."

Franklin understood the basic mechanism of formation of the extensive fogs that can occur over the western Atlantic off eastern Canada. He wrote that:

"as the vapour from a cup of tea in a warm room, and the breath of an animal in the same room, are hardly visible, but become sensible immediately when out in the cold air, so the vapour from the gulph [gulf] stream, in warm latitudes is scarcely visible, but when it comes into the cool air from Newfoundland, it is condensed into the fogs, for which those parts are so remarkable."

Franklin wondered if lightning was in fact an electrical phenomenon. In 1750, he hypothesized that electricity could be taken from clouds via a tall metal aerial insulated from the ground. To do this, he proposed bringing a grounded lead with an insulated wax handle close to such an aerial, and expected that an electric spark would then discharge from the aerial to the grounding wire. This idea formed the basis of his proposal to study lightning through the use of a kite in an electrical storm. This famous experiment has in fact almost become a myth, with Franklin at its centre. He certainly could not have safely conducted it in the way it is often depicted, with him holding the kite string with an attached key waiting to be struck by lightning! He knew the potential dangers, and had several ideas on how to safely show that electricity was present. For example, he proposed attaching a Leyden Jar (a device for collecting electricity - essentially, a capacitor) to the string. If the jar was empty before flying the kite and full afterwards, then that would be evidence that thunderclouds contain electricity.

Franklin probably carried out his kite experiment in June 1752. Clearly he had to be insulated from the current; otherwise he would have been in danger of electrocution from a lightning strike (and in fact others, such as Prof. Georg Wilhelm Richmann in St. Petersburg, were electrocuted when they tried to repeat Franklin's experiment). Through this experiment, Franklin proved that lightning is a form of electricity. He explained his reasoning later in 1752 in a letter to England in which he gave directions for repeating the kite experiment:

"When rain has wet the kite twine so that it can conduct the electric fire freely, you will find it streams out plentifully from the key at the approach of your knuckle, and with this key a phial, or Leiden jar, maybe charged: and from electric fire thus obtained spirits may be kindled, and all other electric experiments [may be] performed which are usually done by the help of a rubber glass globe or tube; and therefore the sameness of the electrical matter with that of lightning completely demonstrated."

The results of the kite experiment were not formally published until Joseph Priestley's 1767 History and Present Status of Electricity. Franklin's own publication Experiments and Observations on Electricity, Made at Philadelphia in America…to Which are Added, Letters and Papers on Philosophical Subjects (London, 1769) came two years later. This book presents his investigations on electricity, his kite experiments, and his invention of the lightning conductor.

Franklin's electrical experiments led directly to his invention of the lightning rod. He surmised that large conductors with a sharp rather than a smooth point could be of use in protecting buildings from lightning. These conductors would be "upright Rods of Iron, made sharp as a Needle and gilt to prevent Rusting, and from the Foot of those Rods [would extend] a Wire down the outside of the Building into the Ground;...Would not these pointed Rods probably draw the Electrical Fire silently out of a Cloud before it came nigh enough to strike, and thereby secure us from that most sudden and terrible Mischief!" Following a series of experiments on Franklin's own house, such lightning rods were installed on the Academy of Philadelphia (later the University of Pennsylvania) and the Pennsylvania State House (later Independence Hall) in 1752. They were so successful that people wanted to make lighting rods for themselves. In fact, lighting rod apparel even became fashionable for a time!

Prokop Diviš erected the first practical European lightning rod in Moravia in 1754, two years after Franklin's first lightning rods in America.

Franklin designed a model "thunder house" to showcase the effectiveness of his lightning rod. In it was a can filled with flammable gases. When static electricity was applied to the top of the house, the electricity traveled down a wire to the can where it made a spark which ignited the gases, blowing the lid of the can off with enough force to knock the roof off the house. However, with a lightning rod is attached to the top of the house, the static electricity was safely transported to the ground and the house was spared.

Franklin considered the Aurora Borealis, and concluded (erroneously) that it must be related to atmospheric circulation patterns.

Franklin happened upon the principle of refrigeration by observing that on a very hot day, he stayed cooler in a wet shirt in a breeze than he did in a dry one. In an experiment one warm day in Cambridge, England in 1758, Franklin and fellow scientist John Hadley experimented by continually wetting the ball of a mercury thermometer with ether and using bellows to evaporate the ether. With each subsequent evaporation, the thermometer read a lower temperature, eventually reaching 7°F (-14°C). Another thermometer showed the room temperature to be constant at 65°F (18°C). In his note Cooling by Evaporation, Franklin concluded that "one may see the possibility of freezing a man to death on a warm summer's day."

Franklin was living in Paris in 1783 (he was the first American ambassador to France, from 1776 to 1785) when the volcano Laki in Iceland erupted (Iceland Scott 577 commemorates the 200th anniversary of the event). The eruption in fact lasted eight months, from June 1783 to February 1784. In the second half of 1783, a persistent haze referred to as a "dry fog" covered Europe, and was observed to be the densest European dry fog since the eruption of another volcano, Eldgjá, in 934 AD. The following winter (1783-1784) was very cold both in Europe and in eastern North America. Franklin concluded that volcanic eruptions could be related to the dry fog and the subsequent cold weather:

"During several of the summer months of thc year 1783, when the effect of the sun's rays to heat the earth in these northern regions should have been greater, there existed a constant fog over all Europe, and great part of North America. This fog was of a permanent nature; it was dry, and the rays of the sun seemed to have little effect towards dissipating it, as they easily do a moist fog, arising from water. They were indeed rendered so faint in passing through it, that when collected in the focus of a burning glass they would scarce kindle brown paper. Of course, their summer effect in heating the earth was exceedingly diminished. Hence the surface was early frozen. Hence the first snows remained on it unmelted, and received continual additions. Hence the air was more chilled, and the winds more severely cold. Hence perhaps the winter of 1783-1784 was more severe than any that had happened for many years.

The cause of this universal fog is not yet ascertained. Whether it was adventitious to this earth, and merely a smoke, proceeding from the consumption by fire of some of those great burning balls or globes which we happen to meet with in our rapid course round the sun, and which are sometimes seen to kindle and be destroyed in passng our atmosphere, and whose smoke might be attracted and retained by our earth; or whether it was the vast quantity of smoke, long continuing to issue during the summer from Hecla in Iceland, and that other volcano which arose out of the sea near that island, which smoke might be spread by various winds, over the northern part of the world, is yet uncertain. It seems however worth the enquiry, whether other hard winters, recorded in history, were preceded by similar permanent and widely extended summer fogs. Because, if found to be so, men might from such fogs conjecture the probability of succeeding hard winter, and of the damage to be expected by the breaking up of frozen rivers in the spring; and take such measures as are possible and practicable, to secure themselves and [their] effects from the mischiefs that attended the last."

In this explanation, Franklin mentions Hecla (which erupted in 1768) and "another volcano which rose out of the sea"; one supposes that he must really have been referring to Laki. He was therefore one of the first (if not the first) to consider the effects of volcanic eruptions on the weather and climate, and to suggest that a useful technique to forecast cold winters could be based on those effects. The eruption of the volcano Tambora in 1815 confirmed these ideas: 1816 became the "year without summer" over parts of America and Europe.

In Paris on 27 August 1783, J.A.C. Charles launched the first balloon inflated with hydrogen gas. Franklin witnessed this launch and later described the crowd's extravagant speculations as to the uses to which such an invention could be put. Franklin himself considered that "possibly it may pave the way to some Discoveries in Natural Philosophy of which at present we have no Conception". Franklin was right: such balloons would soon be used (by Charles himself and others) as the earliest platforms from which measurements of variables such as temperature and humidity in the atmosphere above the surface could be made. These would indeed be new "Discoveries in Natural Philosophy".

Perhaps Franklin's contributions to science and to the politics of his country are best summarized in an epigram on a French bust of him, which states simply that "He wrested the flash of lightning from heaven and the scepter from the tyrants."

Euler, Leonard (1707 - 1783)

Euler was a Swiss mathematician who studied a variety of problems in pure and applied mathematics. He worked extensively in the field of hydrodynamics, and in September 1755 presented a memoir entitled Principes généraux du mouvement des fluides ("General principles of fluid motion") to the Académie royale des Sciences et Belles-Lettres of Berlin. This led to a paper published for a wider audience in 1757. In it, he described the concept of an internal pressure field in a fluid, which allowed him to apply Newton's second law of motion to infinitesimal fluid elements, and in turn to derive a set of hydrodynamical equations. In effect, his work formed the basis for the science of fluid motion, and Euler's equations have since found application in many studies of fluids, including studies of atmospheric flow and atmospheric turbulence.

Euler's name is attached to one common frame of reference used in fluid dynamics and atmospheric studies, known as the Eulerian frame of reference. In it, measurements are made at a fixed point in a moving fluid, and the equations of motion are written with reference to that fixed point. (The Lagrangian frame of reference is the other one that is commonly used).

Euler also had a passing interest in the aurora. In 1746, he suggested erroneously that the aurora consisted of "particles from the Earth's own atmosphere driven beyond its limits by the impulse of the sun's light and ascending to a height of several thousand miles". He believed that the aurora are common in polar regions because "near the Poles, these particles would not be dispersed by the Earth's rotation".

de Buffon, Georges Louis Leclerc (Comte de Buffon) (1707 - 1788)

Buffon was a French naturalist, biologist, mathematician and the keeper of the Royal Botanical Garden near Paris. He studied a wide variety of scientific topics, and attempted in his Histoire naturelle, générale et particulière to present the entire sum of knowledge of natural history and related sciences in a single massive work.

Buffon noted that different regions could have distinct animals and plants despite similar environments. He believed that animal species originated in a "centre of creation" and that they could improve or degenerate during a movement away from that centre. He felt that such a spreading-out must have been facilitated by changes in the climate.

Buffon proposed that the flora and fauna of the New World were inferior to those of Europe, through, among other things, some defective characteristics of its climate. He wrote in the Histoire naturelle that "In America, therefore, animated Nature is weaker, less active, and more circumscribed in the variety of her productions; for we perceive, from the enumeration of the American animals, that the number of species is not only fewer, but, in general, that all the animals are much smaller than those of the Old Continent... In this New World, therefore, there is some combination of elements and other physical causes, something that opposes the amplification of animated Nature: there are obstacles to the development... These effects must be referred to the quality of the earth and atmosphere, to the degree of heat and moisture, to the situation and height of mountains, to the quantity of running and stagnant waters, to the extent of forests, and, above all, to the inert condition of Nature in that country. In this part of the globe, the heat in general is much less, and the humidity much greater".

Thomas Jefferson and James Madison realized that this thesis had to be refuted if America were to be considered as a peer by the European nations. To this end, they conducted their own programs of weather observations as well as studies of American fauna.

Lomonosov, Mikhail V. (1711 - 1765)

Lomonosov was a pioneering Russian scientist who came to be known as the Father of Russian Science. He worked in a wide variety of scientific areas.

In 1732 Vitus Bering was placed in charge of five epic voyages of exploration of eastern and northern Russia and the Arctic ocean by the Empress Anna. They lasted from 1733 to 1742 and came to be known as the Great Northern Expeditions. Lomonosov helped organize these expeditions. He ensured that each ship had the necessary physical and astronomical instruments and developed special ship log books and meteorological log books. He wrote a book in 1763 that described the various explorations of the northern seas from the earliest expeditions to the Great Northern Expeditions. In it he presented his ideas on Arctic ocean currents, sea ice drift, sea ice type and the dependence of the freezing point on the salinity of the water. He also explained the role of the sun as an Arctic heat source and theorized that an exchange of heat through the ice from the water below to the atmosphere above could moderate the cold Arctic temperatures. In addition, he presented one of the first scientific explanations of the aurora borealis.

Around 1750, Lomonosov designed a rotational anemometer: a vertical wheel equipped with vanes (like a small water wheel) that was turned by the wind. This wheel was oriented into the wind by a large flag-shaped paddle that acted as a wind vane. By means of teeth and a cord, this motion was transmitted to a secondary wheel equipped with a speed scale. In addition, the instrument design included a source of mercury that was able to fall into various bins (small boxes) of wind direction. At least in theory, the distribution of wind direction in a given time period could be determined by measuring the amount of mercury that fell into each box during that period.

Bošković, Rudjer Josip (1711 - 1787)

Bošković was a Croatian scientist who worked in a wide variety of disciplines. He wrote some 70 papers on many subjects including optics, astronomy, gravitation, meteorology and trigonometry. He also made observations of the aurora borealis, and following an episode in December, 1837 estimated the height of the aurora to be about 1000 km (600 miles). He also put forth some hypotheses about the causes of the aurora.

Diderot, Denis (1713 - 1784)

Diderot was a French philosopher and writer. In the Encyclopédie, ou Dictonnaire raisonné des Sciences, des Arts et des Métiers (earliest edition published in 1751 in France by Diderot and d'Alembert), Diderot included one of the earliest definitions of modern meteorology. He wrote: "From the study, conducted with the senses, of wind, rain, hail, thunder, etc, consideration has passed to the determination of their origins, causes, effects, etc, and produced the science called meteorology". Diderot also discussed "meteors" (Météores, comme vents, pluies, tempêtes, tonnerres, aurores boréales, etc - "Meteors", such as winds, rain, storms, thunder, the Aurora Borealis, etc). In the language of the time, "meteor" referred generally to "a body or an appearance of a body in the atmosphere that is formed from substances that float there". The modern word "meteorology" has as its root the word "meteor" in this sense. The Encyclopedia embodied the spirit of the Enlightenment, and Diderot's foreshadowing of the modern science of meteorology flowed natuarally from that spirit.

Juan, Jorge (1713 - 1773)

Juan was a Spanish explorer and writer. In 1754 he founded the Marine Guards Company Observatory in Cádiz. Some meteorological observations were made there, though they were not systematic and were not recorded. Before his death in 1773, Juan deplored the lack of interest in making meteorological observations and in taking care of the expensive meteorological instruments that had been imported from England. The original Observatory declined after Juan's death, but a new one completed in 1797 on the same site renewed Spanish meteorological and other scientific work and became known as the Spanish Nautical Observatory.

d'Alembert, Jean Le Rond (1717 - 1783)

D'Alembert was a French mathematician who pioneered the use of partial differential equations in studies of fluid motion. His work on this topic first appeared in a study on winds entitled Réflexions sur la cause générale des vents (Thoughts on the Origins of the Winds) submitted to the Berlin Academy in 1747. In it, d'Alembert assumed that the winds were generated by tidal effects on the atmosphere and that heating played only a minor role. It is now known that solar heating is the ultimate driver of the atmospheric circulation and winds. Nevertheless d'Alembert's work was mathematically sound and presented for the first time the equations of motion of an incompressible fluid on the two-dimensional Earth's surface represented in spherical coordinates.

Euler recognized the power of d'Alembert's methods and incorporated them into his own work on fluid motion.

With Diderot, d'Alembert was one of the first contributors to the French Encyclopédie, ou Dictonnaire raisonné des Sciences, des Arts et des Métiers.

Hell, Maximilian (1720 - 1792)

Hell was a Jesuit astronomer, mathematician, writer and director of the Central Observatory in Vienna. In 1767 he accepted an invitation from King Christian VII of Denmark and Norway to direct a scientific expedition to northern Norway with the primary goal of observing the transit of Venus and the subsequent eclipse. During the expedition, which lasted from 1768 to 1770, Hell studied the Aurora Borealis and developed a theory for their origin. He and his team also collected scientific data on biology, meteorology, oceanography, zoology, geography, natural history and linguistics for an encyclopedia of the Arctic regions that they hoped to publish. Unfortunately, the encyclopedia was abandoned because of the suppression of the Society of Jesuits in 1773.

Kant, Immanuel (1724 - 1804)

Kant was a Prussian philosopher who was also interested in natural science. He published works on aesthetics and ethics and in a wide range of scientific fields including physics, astronomy, geology, meteorology, anthropology and psychology.

Cook, James (1728 - 1779)

Cook was an English explorer and scientist. His voyages to the Pacific, unprecented for the time in their scope, were both journeys of exploration and of science. Observations were made in a variety of scientific disciplines, from ethnology and anthropology through botany and biology to glaciology¹ and meteorology. Cook's ships made the first recorded observations² of the Aurora Australis (the Southern Hemisphere aurora) in 1773 during his second expedition (1772-1775). Among the members of that expedition were the astronomer and meteorologist William Wales and the naturalists J. R. Forster and his son Georg Forster.

¹For example: Around 12 January 1773: "a thermometer was sent down 100 fathoms and when it came up the mercury was at 32 [°F] which is the freezing point, some little time after, being exposed to the surface of the Sea, it rose to 33½ and in the open air to 36. Some curious and intresting experiments are wanting to know what effect cold has on Sea Water". The next day, according to Forster, "Capt Cook took a half pint pot filled it with small Ice to the very top & filled the interstices with water: then was the pot set before the fire. Some particles of Ice were standing above the Surface of the water & the brim of the pot so that it might be said it were more than full. As soon as the Ice began to melt the water sunk gradually in the pot, till at last there was not the least Ice left & the water was ¼ of an Inch below the brim of the pot."

²Wales' observation: On 16 January 1773 William Wales, the astronomer, missed the first sighting of the Aurora Australis. The next day he recorded "I... found it to be the very same phenomenon which we call the Northern Lights in England. The natural state of the heavens, except in the S.E. quarter, and for about 10° of altitude all round the horizon, was a whitish haze, through which stars of the third magnitude were just discernable. All round, the horizon was covered with thick clouds, out of which arose many streams of a pale reddish light, that ascended towards the zenith. These streams had not that motion which they are sometimes seen to have in England but were perfectly steady, except a small tremulous motion which some of them had near their edges".

²An observation by the crew of the Adventure: In February 1773, Tobias Furneaux, master of the Adventure [the companion ship to Cook's Resolution] "kept between the Latitude of 52° and 53° South, had much Westerly winds hard gales with squalls, snow and sleet with a long hollow sea from the SW Quarter so that we judge there is no Land in that quarter... On the 26th [of February 1773] at night we saw a Meteor of an uncomon brightness in the NNW, it directed its' course to the SW with a very great light in the southern sky, such as is known to the Northward by the name Aurora Borealis, or Northern Lights: We saw the Lights for several nights running; and what is remarkable we have seen but one Island of Ice since we parted company with the Resolution..."

See the following web sites for additional philatelic information on Captain Cook:

• Captain Cook's Philatelic Site
• Captain James Cook Through Stamps
• Captain James Cook The Explorer: An Historical & Philatelic Review