An anemoscope is a device designed to show the direction of the

wind Wind is the natural movement of atmosphere of Earth, air or other gases relative to a planetary surface, planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heatin ...

, or to indicate a change of wind direction. The name is usually applied to an apparatus consisting of a

wind vane A wind vane, weather vane, or weathercock is an list of weather instruments, instrument used for showing the wind direction, direction of the wind. It is typically used as an architectural ornament to the highest point of a building. The word ' ...

above, connecting to a building below by some kind of coupling, and with a dial or index with pointers to show the direction and changes of the wind. Anemoscopes existed in antiquity and have evolved into modern mechanical and electronic instruments. The word is first recorded in English in the period 1700–10. It derives from the Greek word for wind + -scope. Should not be confused with the

anemometer In meteorology, an anemometer () is a device that measures wind speed and direction. It is a common instrument used in weather stations. The earliest known description of an anemometer was by Italian architect and author Leon Battista Alberti ...

, a device to measure the speed of the wind, alongside which it is often deployed.

History

In antiquity the direction of the wind was indicated by the direction of smoke or the lifting of a flag. The anemoscope then formed a base by which the formal direction of the wind could be gauged. The wind indicator (anemoscope) of

Timosthenes Timosthenes of Rhodes (Greek: ) (fl. 270 BCE) was a Greek navigator, geographer and admiral in Ptolemaic navy. He is credited with inventing the system of twelve winds that became known as the Greek 12-wind rose. Career In the 280s–270s BCE, ...

(fl. 270 BCE) consisted of a disc with radius which indicated the direction of the system of twelve winds devised by him . (Aparctias, Boreas, Kaikias, Apeliotes, Euros, Euronotos, Notos, Libonotos, Lips, Zephyros, Argestes, Thrascias).

Tower of the Winds The Tower of the Winds, known as the in Greek, and by #Names, other names, is an octagonal Pentelic marble tower in the Roman Agora in Athens, named after the eight large reliefs of wind gods around its top. Its date is uncertain, but was compl ...

, is 2nd century BC structure in Athens. A bronze Triton once served as a weather-vane but has been lost. Eight sculptures remain around the base. These bass relief flying figures representing the winds, and under each was once a sun-dial.There was also a water-clock. As the tower was forty feet in height and twenty-seven in diameter, it still forms a striking object. This Tower of the Winds is the oldest known construction for observing the winds, Vatican_anemoscope

An ancient anemoscope described by

Vitruvius Vitruvius ( ; ; –70 BC – after ) was a Roman architect and engineer during the 1st century BC, known for his multi-volume work titled . As the only treatise on architecture to survive from antiquity, it has been regarded since the Renaissan ...

(1st century BCE), seems to have been intended to show which way the wind actually blew, rather than to foretell into which quarter it would change. The later anemoscope of Eftropiou is of similar design.

Hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

devices, in particular those utilizing

catgut Catgut (also known as gut) is a type of cord that is prepared from the natural fiber found in the walls of animal intestines. Catgut makers usually use sheep or goat intestines, but occasionally use the intestines of cattle, hogs, horses, mules, ...

, were considered as very good anemoscopes, seldom failing to foretell the shifting of the wind. The German

Otto von Guericke Otto von Guericke ( , , ; spelled Gericke until 1666; – ) was a German scientist, inventor, mathematician and physicist. His pioneering scientific work, the development of experimental methods and repeatable demonstrations on the physics of ...

(1602-1686) gave the title ''anemoscope'' to a machine invented by him to foretell the change of the weather, as to fair and rain. It consisted of a small wooden man who rose and fell in a glass tube as the atmospheric

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and eve ...

increased or decreased. Accordingly, M. Comiers has shown that this was simply an application of the common

barometer A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis ...

. This form of the anemoscope was invented by

Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 1452 - 2 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially rested o ...

. In the industrial era the anemoscope became a mechanical device for transferring the point of direction of a wind vane to a display panel, or recording scroll. It achieved this through a mechanical linkage and later by an electrical signal. Anemoscope Pendley Manor Hertfordshire

An example of a Victorian amenoscope (c1875) is located in the

English country house image:Blenheim - Blenheim Palace - 20210417125239.jpg, 300px, Blenheim Palace - Oxfordshire An English country house is a large house or mansion in the English countryside. Such houses were often owned by individuals who also owned a Townhou ...

, Pendley Manor in Hertfordshire. It is a large wooden dial with a pointer showing the current wind direction powered by the pressure of the wind on a vane on top of the house. An anemoscope c1920s built by the American instrument maker Julien P. Friez & Sons is in the collection of Harvard university was designed to be used as part of an automatic wind recorder alongside a wind speed measuring

. Today anemoscopes are used in

meteorological stations Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agriculture, ...

, and in transport especially boats. A marine anemoscope will often show the direction of the wind in relation to the directions of the boat (ie fore, aft,

starboard Port and starboard are Glossary of nautical terms (M-Z), nautical terms for watercraft and spacecraft, referring respectively to the left and right sides of the vessel, when aboard and facing the Bow (watercraft), bow (front). Vessels with bil ...

and port) rather than the

cardinal direction The four cardinal directions or cardinal points are the four main compass directions: north (N), south (S), east (E), and west (W). The corresponding azimuths ( clockwise horizontal angle from north) are 0°, 90°, 180°, and 270°. The ...

s (north, south, east and west).

References

Sources

*{{1728, title=Anemoscope *Solari, G. (2019). The Wind and the New Science. In: Wind Science and Engineering. Springer Tracts in Civil Engineering. Springer, Cham. https://doi.org/10.1007/978-3-030-18815-3_3 Pressure gauges Meteorological instrumentation and equipment

History

See also

References

Sources