I saw the different things you did,
But always you yourself you hid.
I felt you push, I heard you call,
I could not see yourself at all
Robert Louis Stevenson. 1913. "The Wind," in A Child's Garden of Verses: Selected Poems. Lit2Go Edition, (1913), accessed October 15, 2016,
http://etc.usf.edu/lit2go/59/a-childs-garden-of-verses-selected-poems/4761/the-wind/.
There are things you can't talk about or visualize or even begin to understand until you have the right tools. Until William Morrison and John C. Wharton built the first machine in 1897, you just couldn't get cotton candy.
1 What's remarkable to me is that until 1450, when Leon Battista Alberti invented the anemometer, we had no way of quantifying, even roughly, how fast the wind was blowing.
The Greeks were avid meteorologists (since they came up with the word "meteorology," that isn't really surprising).
2 When it came to understanding winds, they went to enormous efforts, constructing Athens' octagonal "Tower of the Winds" sometime around 50 BCE (or perhaps earlier) to study the winds.
But keep in mind, when I say "study" I just mean "classify in terms of direction."
Aristotle (c. 340 BCE) recognized 10 wind directions; Timosthenes of Rhodes (c. 282 BCE) recognized 12; Vitruvious (c. 15 BCE) recognized 24; and in the Middle Ages, European mariners recognized 16 wind directions (and sometimes as many as 32).
Wind direction is important, of course. But what about wind speed?
Remarkably enough, the first instrument to measure wind speed wasn't invented until the 15th century. Leon Battista Alberti's (1404-1472) anemometer was about as simple as an instrument can get -- a hinged flat plate was allowed to swing in the wind. The angle of the plate could be measured -- which meant that for the first time
ever, wind speed could be quantified.
A simple pressure plate anemometer based on Robert Hooke's (1635-1703) design.
Until Alberti invented the anemometer there just wasn't any way to quantify or compare the speed of the wind.
Or was there?
In 1704 Daniel Defoe (c. 1660-1731 -- yes, the
Robinson Crusoe Daniel Defoe) proposed an 11-point scale of the winds (National Meteorological Library 2007):
- 0 Stark Calm
- 1 Calm Weather
- 2 Little Wind
- 3 A Fine Breeze
- 4 A Small Gale
- 5 A Fresh Gale
- 6 A Topsail Gale
- 7 Blows Fresh
- 8 A Hard Gale of Wind
- 9 A Fret of Wind
- 10 A Storm
- 11 A Tempest
Defoe doesn't seem to have tried to quantify these speeds, but "during the late 17th century sailors were using a fairly standard set of names to describe winds" (Singleton 2016).
In 1759 John Smeaton (1724-1792), a brilliant engineer, architect and inventor, devised an eight point scale for describing the speed of the wind and its effect on windmills.
John Smeaton's 1759 anemometer.
John Smeaton's scale of wind velocity.
Source: Smeaton 1814, p. 64)
Smeaton expressed wind speed in terms of feet per second, and was primarily interested in the efficiency of windmills.
3
In 1779 Alexander Dalrymple of the East India Company (1737-1808) produced a similar wind scale, as did Archibald Menzies (1754-1842) about 1791. Dalrymple (1737-1808), the Royal Navy's first official Hydrographer, became interested in the idea of some kind of standardized way to describe wind speeds, and apparently intended to publish Smeaton's scale in his book,
Practical Navigation in 1790 -- but the book was never published. However "there's compelling evidence that Beaufort actually copied [his original] scale directly out of a pamphlet written by Alexander Dalrymple" (Huler 2004, pp. 72-73).
James Capper (1743-1825), a British officer who worked for the East India Company, produced a combined scale of wind speed and descriptions (Capper 1801, p. 226; see also National Meteorolgical Library and Archive 2007):
James Capper's 1801 scale of wind speeds and descriptive terms.
From 1660 British captains were required to keep weather logs (logbooks were valuable -- they gave information about what other ships might encounter). In 1805 Francis Beaufort took command of the HMS
Woolwich. In his log for January 13, 1806 he wrote that he had devised a 13-point scale for wind speed, and began to use it to record his weather observations (Singleton 2016; National Meteorological Library and Archive 2007).
It's a bit hard to read the diary, but this is the original scale:
Beaufort's original 13 point scale.
What's remarkable about this scale?
Nothing.
"If this was the Beaufort scale, then the Beaufort scale wasn't much" (Huler 2004, p. 73)
"The original Beaufort scale ... is merely a scale of wind conditions that was used by sailors to categorize the different sailing conditions" (Wallbrink and Koek 2005, p. 3).
That's right -- the original version of the Beaufort scale was amazingly ordinary. The words are nicely descriptive. And the numeric values are reasonable. But there is absolutely nothing here that adds materially to what Defoe wrote in 1704. It's markedly inferior to both Capper's and Smeaton's scales. So why do we still rhapsodize about Beaufort?
Because the story's not done.
In 1807, while in the harbor at Montevideo, Uruguay, Beaufort wrote an updated version of his scale. For the first time he defined his wind forces in terms of something observable: his ship's sails and behavior (Hulter 2004, p. 73-75). His new scale looked like this:
 |
The 1807 version of the Beaufort scale.
|
This was a crucial change. Instead of simply assuming that all experienced sailors would mean roughly the same thing when they said "light air" or "moderate gale," there was now a way of describing, categorizing and measuring (in a relatively objective way) the force of the winds: by looking at how the ship responded to the wind.
Beaufort continued to refine his scale. In 1831 Captain Robert Fitzroy asked the Royal Navy Hydrographer to find a suitable naturalist for his ship, the HMS
Beagle. The naturalist selected was Charles Darwin. The Hydrographer was Francis Beaufort (Hulter 2004, pp. 121-123). In addition to finding the most gifted naturalist imaginable, Beaufort also provided Captain Fitzroy with the newest version of his scale; the
Beagle was the first ship to officially employ the Beaufort scale for its weather observations (Foster and Chesney 1998, pp. 328-329). Beaufort also submitted his still further revised scale of wind forces to the Admiralty. In 1838 it was adopted as the standard for use by all ships in the British Navy.
This is the "classic" 1838 version of the Beaufort Scale:
In 1874 "Beaufort’s scale of wind force was revised ... to reflect changes in the rig of warships, and expanded two decades later to include particulars of the sail required by fishing smacks"; in 1903 wind speeds (rather than wind forces) were computed using a formula:
V = √ 1.87 * B3
Where
V is the wind speed in miles per hour 30 feet above the surface of the sea, and
B is the Beaufort number (National Meteorological Library and Archive 2007).
In 1906 the British Meteorology Office published a revised version of the Beaufort scale that now included something revolutionary: observations not of the ship, but of the sea. Ships came in a much larger variety, the age of sail was ending. Now, instead of observing the characteristics of your vessel, you would observe your environment. And not just a marine environment. Now there were descriptions and Beaufort numbers for the land as well:
 |
The 1906 revision of the Beaufort scale
Source: Huler 2004, p. 78. |
It's a bit hard to see here, but this goes much further -- now there is a column describing wind speed on land as well -- for example, at Force 2 "Wind felt on face; leaves rustle; ordinary [weather] vane moved by wind"; at Force 6 "Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty"; at Force 9 "Slight structural damage (chimney pots and slates removed." What had been a tool for sailors was becoming a tool for everyone.
And the revising went on. In 1921 Captain H.P. Douglas (later Sir Percy Douglas) devised a 9 point "sea scale" to describe wave height and sea conditions:
Degree Height (m) Description
0 no wave Calm (Glassy)
1 0–0.10 Calm (rippled)
2 0.10–0.50 Smooth
3 0.50–1.25 Slight
4 1.25–2.50 Moderate
5 2.50–4.00 Rough
6 4.00–6.00 Very rough
7 6.00–9.00 High
8 9.00–14.00 Very high
9 14.00+ Phenomenal
This could then be combined with a "swell of the sea" scale:
Degrees Description
0 No swell
1 Very Low (short and low wave)
2 Low (long and low wave)
3 Light (short and moderate wave)
4 Moderate (average and moderate wave)
5 Moderate rough (long and moderate wave)
6 Rough (short and heavy wave)
7 High (average and heavy wave)
8 Very high (long and heavy wave)
9 Confused (wavelength and height indefinable)
And then combined with wave length and wave height information:
| Wavelength | |
|---|
| Short wave | 100 m - |
| Average wave | 100-200 m |
| Long wave | 201 m + |
| Wave height | |
| Low wave | 2 m - |
| Moderate wave | 2-4 m |
| High wave | 4.01 m + |
To produce the Douglas Sea and Swell Scale:
In 1926 the International Commission for Weather Telegraphers adopted the 1906 Beaufort scale as an international standard.
In 1927 Captain Peter Petersen published a "state of the sea" scale with extremely vivid descriptions. of the state of the sea which were correlated with the Beaufort scale (Huler 2004, pp. 198-199; BORDGEMEINSCHAFT D187 2016):
| Sea Surface | Description | Wavelength | Wave Height | Beaufort |
|---|
| 0 | Mirror-like surface. | 0-5 m | 0-0.25 m | 0 |
| 1 | Small scale-covered ripples without crests. | 5-15 m | 0-0.25 m | 1 |
| 2 | Small waves, short but pronounced. Combs look glassy and do not break. | 15-25 m | 0.25-1 m | 2 |
| 2 | Combs begin to break. Foam mostly glassy, isolated small white foam heads can occur. | 15-25 m | 0.25-1 m | 3 |
| 3 | Waves small but longer. White foam heads common. | 25-50 m | 0.75-1 m | 4 |
| 4 | Moderate waves with a long form. White foam crests everywhere. Isolated spray can be seen. | 50-75 m | 2-4 m | 5 |
| 5 | Large waves start to form. Wave crests break and leave large white foam surfaces. There is some spray. | 75-100 m | 3-6 m | 6 |
| 6 | Sea piling up. White foam breaks into stripes in the wind direction. | 100-135 m | 5-7 m | 7 |
| 7 | Moderately high to mountainous waves with crests of considerable length. Spray begins to blow off the crests. Foarm lies in well-marked stripes in the wind direction. | 150-200 m | 7-10 m | 8 |
| 7 | High mountainous waves. Dense foam streaks in the wind direction. Rolling seas begin. Spray can affect visibility. | 150-200 m | 7-10 m | 9 |
| 8 | Very high waves with long breaking ridges. Seas are white with foam. Heavy rolling seas. Visibility impaired by spray. | 200-250 m | 10-15 m | 10 |
| 9 | Exceptionally high waves, visibility reduced by spray. | 250 300 m | 10-15 m | 11 |
| 9 | Air filled with foam and spray. Sea completely white. Visibility very low, long distance visibility impossible. | > 300 m | > 15 m | 12 |
Petersen's sea-state scale (my translation)
In 1935 the International Meteorological "asked several countries to test the Petersen state-of-the-sea scale, and it was finally adopted in 1947" (Huler 2004, p. 200). The World Meteorological Organization adopted the Beaufort scale, with minor revisions, in 1970:
And now, after all that, here's what the World Meteorological Society has to say about the Beaufort scale today:
"... while sea state reporting remains a legal international practice, with modern in situ observing techniques we try to avoid using sea state or Beaufort scale as we prefer direct readings from appropriate instruments" (Marine Meteorology and Oceanography Programme FAQ; Online: http://www.wmo.int/pages/prog/amp/mmop/faq.html#sea_state).
Not really a rousing endorsement, is it? "If you insist you can use; it's
legal. But we'd really rather you didn't." Kind of dismissive, in fact.
Not that this means the Beaufort scale is going to be abandoned any time soon. It's incredibly useful to be able to just look at the world around you and be able to say with confidence that when you can feel the wind on your face and leaves rustle that the wind is blowing at about 6-11 kph (4-7 mph).
It's more than just useful. It's
empowering.
You can't tell the temperature, or the air pressure, or the humidity just by looking. But you can know the speed of the wind. And that is amazing.
The thing that surprises me is that it took something like 2,000 years to achieve that insight. Vitruvius (Marucs Vitruvius Pollio, 80-15 BCE) wrote about the importance of understanding both wind direction and wind force:
"Wind is a flowing wave of air, moving hither and thither indefinitely. It is produced when heat meets moisture, the rush of heat generating a mighty current of air. That this is the fact we may learn from bronze eolipiles [bronze balls partially filled with water -- effectively, teapots], and thus by means of a scientific invention discover a divine truth lurking in the laws of the heavens" (Book I, Chapter 6).
"... sails that are only halfway up have less effect, but when they get farther away from the centre, and are hoisted to the very top of the mast, the pressure at the top forces the ship to make greater progress, though the wind is no stronger but just the same" (Book X, Chapter 3).
But Vitruvius never bothered to try and find some way of measuring that force.
Meteorological instruments were invented over an astonishingly long period of time:
- Leonardo da Vinci invented a kind of hygrometer (to measure humidity) in 1480.
- Galileo is usually given the credit for inventing the thermometer (thermoscope) in 1593. However, the earliest temperature measuring device seems to have been invented by Philo of Byzantium some time around 250 BCE (there is still a class of devices called "Philo thermometers") (McGee 1988, p. 3).
- Air pressure (barometric pressure) was first measured by Evangelista Torricelli (1608-1647) in 1643.
- The first rain gauges were probably invented in India around 2,300 years ago, and in Palestine about the same time. The first actual use of rain gauges for large-scale meteorological research were in Korea in 1441 (Strangeways 2010).
- The first device to measure incoming solar radiation was invented in 1825 by Sir John Frederick William Herschel (Coulson 2012, p. 55).
Weather is something that affects all of us. And it took more than 2,000 years to devise the things we need to understand it.
The real issue isn't technological. The issue is learning to
see. Learning to think beyond the way things
are, to
why things are. There was certainly nothing technologically advanced or exotic about Alberti's (or Robert Hooke's) pressure plate anemometers; any halfway skilled blacksmith in ancient Rome could have whipped one up. But that's missing the point. Until Leon Battista Alberti actually put up a sheet of metal next to a scale,
nobody had ever measured wind speed.
What prompted him to do this? It's hard to say. Alberti was a genius, an "author, artist, architect, poet, priest, linguist, philosopher, and cryptographer, and general Renaissance humanist polymath" (Norman 2016; see also Nesfield-Cookson 2010, p. 64), and he lived in one of the most intellectually lively places the world has ever seen. He was a contemporary of artists, architects and scientists, like Lorenzo Ghiberti, Filippo Brunelleschi, Donatello, Fra Angelico, Michelangelo Buonarroti, Giovanni Bellini, Paolo dal Pozzo Toscanelli and Leonardo Da Vinci; and he worked for Popes Eugenius IV, Nicholas V, and Pius II. When you let geniuses talk to other geniuses -- things happen.
But keep in mind, the idea of measuring something that can't be seen -- like wind -- should not have been all that revolutionary. The hydrological cycle was well known nearly 3,000 years ago:
The sea is the source of water and wind,
for without the great sea there would be no wind
nor streams of rivers nor rainwater from on high;
but the great sea is the begetter of cloujds, winds,
and rivers.
Xenophanes of Colophon, fragment 30 (570-475 BCE) (Lesher 2001, p. 5)
It was Alberti's flash of genius that lead him to finding a way to measure -- in a very fundamental sense, to
see -- what could not be seen.
Beaufort's scale was, to start with, fairly trivial. You could use words to describe how fast the wind blew. But over the last century and a half it was made into an incredibly useful tool. An empowering tool. We see the wind. Using Beaufort's (heavily modified) scale, we can see what is unseeable. We can see the wind.
Notes
1 There were cotton candy-ish things -- Persian
pashmak, or Turkish
pişmaniye, for example -- before true machine-made cotton candy. They aren't the same. At all.
2 Although the ancient Greek "meteorology" was a lot broader than our use of the word. Aristotle in his Meteorology included "all the affections we may call common to air and water, and the kinds and parts of the earth and the affections of its parts," including astronomy, geology, and geomorphology. See UCMP Berkeley online:
http://www.ucmp.berkeley.edu/history/aristotle.html
3The Smeaton coefficient, developed as a result of his experiments, was actually used by the Wright brothers to calculate lift. The formula is L = kV
2 ACl, where
L is lift,
k is the drag coefficient,
A is the area in square feet, and
Cl is the lift relative to the drag. Apparently this isn't used anymore -- but it worked well enough to get the Wright brothers off the ground.
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