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Heron

 
Britannica Concise Encyclopedia: Heron of Alexandria
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(flourished c. AD 62, Alexandria, Egypt) Greek mathematician and inventor. He is remembered for his formula for the area of a triangle and for inventing the aeolipile, the first steam engine, which, in his design, was a forerunner of the jet engine. Of his many treatises, one contains a method for approximating the square root of a number. His writings on mechanics include discussions of the five simple machines, mechanical problems of daily life, and the construction of many kinds of engines.

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Scientist: Heron of Alexandria
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[a.k.a. Hero, b. Alexandria, c. 10 ce, d. c. 75]

Heron is thought to have taught at the Museum in Alexandria, and the books that are attributed to him were probably based on lecture notes, as with Aristotle's works. Many of his writings are known in Greek or in Arabic or Latin translations, including Automaton Making, Geometrica, Mechanica (for architects), Metrica (on measurement), Catopricis (on mirrors), Pneumatics (on mechanical devices worked by air, steam, or water), Siegecraft, and Dioptra (on the surveyor's transit), as well as a fragment on water clocks and parts of a dictionary of technology. His works survived because of a wealth of practical information on wine presses, cranes, pulleys, and the like. He is best remembered today for a pinwheel that operated by steam, often called the first steam engine. He was also a creative mathematician.


Biography: Heron of Alexandria
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The engineer, mathematician, and inventor Heron of Alexandria (active ca. 60) ranks among the most important scientists of the ancient Roman world in the tradition of Aristotelian experimentation.

Heron, about whose personal life virtually nothing is known, resided in Alexandria, Egypt, among the scientists and men of letters of the late Ptolemaic and Roman eras who dwelled around the famed library and museum. A brilliant theoretical scientist and a prolific writer, Heron wrote with clarity and insight. The knowledge of his writings and scientific investigations was preserved in the writings of the late Roman, Byzantine, and Arabic scientists and encyclopedists.

One of Heron's outstanding treatises was the Metrica, a geometrical study, in three volumes, on the measurement of simple plane and solid figures from polygons to hendecagons. It approximates the areas of triangles, polygons, quadrilaterals, ellipses, spheres, circles, and cones, and the volumes of various solids, including the cone, cylinder, and pyramid. In developing the mathematical studies, Heron solved complex quadratic equations arithmetically, approximated the square roots of nonsquare numbers, and calculated cube roots. Heron's other mathematical works include the Definitions, Geometrica, Geodaesia (Land Measurements), Stereometrica (Solid Measurement), Mensurae (Measures), and Liber geëponicus (Book on Agriculture).

In the Mechanica, preserved only in Arabic, Heron explored the parallelograms of velocities, determined certain simple centers of gravity, analyzed the intricate mechanical powers by which small forces are used to move large weights, discussed the problems of the two mean proportions, and estimated the forces of motion on an inclined plane. The Pneumatica, possibly derived from the works of Philo of Byzantium and Ctesibus, describes mechanical devices operated by compressed air, water, or steam. Included are the steam engine, siphon, fire engine, water organ, slot machines, and water fountains. Other works by Heron dealing with the problems of mechanics and engineering are the Barulcus (On Raising Heavy Weights), Belopoeica (Making Darts), On Automaton-making, Catoptrica (On Mirrors), and On the Dioptia. In the last treatise Heron describes a machine called the "Cheirobalistra," which depended on a refined screw-cutting technique and could be used to bore a tunnel through a mountain. He also described an instrument called the hodometer for measuring distances traveled by wheeled vehicles.

Beyond gadgetry, the practical application of Heron's ideas in antiquity was minimal, although they did influence Arabic and Renaissance construction of fountains, clocks, and automated objects. In Heron's time the widespread use of slave labor throughout the Roman world negated most interests in labor-saving devices.

Further Reading

Some fragments of Heron's writings appear in English in Morris R. Cohen and Israel E. Drabkin, A Source Book in Greek Science (1958). Heron's scientific ideas are best presented in A. G. Drachman, The Mechanical Technology of Greek and Roman Antiquity (1963), and Robert S. Brumbaugh, Ancient Greek Gadgets and Mechanics (1966). General books which discuss Heron and ancient science are Marshall Clagett, Greek Science in Antiquity (1955), and L. Sprague de Camp, The Ancient Engineers (1963).

 
Columbia Encyclopedia: Heron of Alexandria
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Heron of Alexandria (hēr'ŏn) or Hero, mathematician and inventor. The dates of his birth and death are unknown; conjecture places them between the 2d cent. B.C. and the 3d cent. A.D. He is believed to have lived in Alexandria; although he wrote in Greek, his origin is uncertain. Several of his works survive either in Greek or in Latin translation. He wrote on the measurement of geometric figures, and a formula for finding the area of a triangle has been ascribed to him. Known for his study of mechanics and pneumatics, he invented many contrivances operated by water, steam, or compressed air; these include a fountain, a fire engine, siphons, and an engine in which the recoil of steam revolves a ball or a wheel.
Wikipedia: Heron
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For other uses, see Heron (disambiguation).
Herons
Snowy Egret, Egretta thula. Note the chicks in the nest.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Subclass: Neornithes
Infraclass: Neognathae
Superorder: Neoaves
Order: Ciconiiformes
Family: Ardeidae
Leach, 1820
Genera

About 17, see text
Synonyms

Cochlearidae

The herons are wading birds in the Ardeidae family. There are 64 recognised species in this family. Some are called egrets or bitterns instead of herons. Within the family, all members of the genera Botaurus and Ixobrychus are referred to as bitterns, and - including the Zigzag Heron or Zigzag Bittern - are a monophyletic group within the Ardeidae. However, egrets are not a biologically distinct group from the herons, and tend to be named differently because they are mainly white and/or have decorative plumes. Although egrets have the same build as the larger herons, they tend to be smaller.

The classification of the individual heron/egret species is fraught with difficulty, and there is still no clear consensus about the correct placement of many species into either of the two major genera, Ardea and Egretta. Similarly, the relationship of the genera in the family is not completely resolved. However, one species formerly considered to constitute a separate monotypic family Cochlearidae, the Boat-billed Heron, is now regarded as a member of the Ardeidae.

Although herons resemble birds in some other families, such as the storks, ibises and spoonbills, they differ from these in flying with their necks retracted, not outstretched. They are also one of the bird groups that have powder down.

Some members of this group nest colonially in trees; others, notably the bitterns, use reedbeds.

Contents

Diet

The members of this family are mostly associated with wetlands, and prey on fish, frogs, invertebrates, rabbits, and snakes. Some, like the Cattle Egret and Black-headed Heron, also take large insects, and are less tied to watery environments.

In February 2005, the Canadian scientist Dr. Louis Lefebvre announced a method of measuring avian IQ based on their innovation in feeding habits. Herons were named among the most intelligent birds based on this scale, reflecting a wide variety, flexibility and adaptiveness to acquire food.[1]

Name

Herons are also known as "shitepokes", or euphemistically as "shikepokes". Webster's Dictionary suggests that herons were given this name because of their habit of defecating when flushed. The terms "shitepoke" or "shikepoke" can be used as insults in a number of situations.[2] For example, the term "shikepoke" appears in the 1931 play Green Grow The Lilacs, and in the 1943 musical play Oklahoma!.

The 1971 Compact Edition of the Oxford English Dictionary describes the use of "shitepoke" for the small green heron of North America (Butorides virescens) as originating in the United States, citing a published example from 1853. The OED also observes that "shiterow" or "shederow" are terms used for herons, and also applied as derogatory terms meaning a "thin weakly person". This name for a heron is found in a list of gamebirds in a royal decree of James VI (1566 -1625) of Scotland. The OED speculates that "shiterow" is a corruption of "shiteheron".[3]

Taxonomy and systematics

Analyses of the skeleton, mainly the skull, suggested that the Ardeidae could be split into a diurnal and a crepuscular/nocturnal group which included the bitterns. From DNA studies and skeletal analyses focusing more on bones of body and limbs, this grouping has been revealed as incorrect[4]. Rather, the similarities in skull morphology reflect convergent evolution to cope with the different challenges of daytime and nighttime feeding. Today, it is believed that three major groups can be distinguished[5], which are (from the most primitive to the most advanced):

  • tiger herons and the boatbill
  • bitterns
  • day-herons and egrets, and night-herons

The night herons could warrant separation as subfamily Nycticoracinae, as it was traditionally done. However, the position of some genera (e.g. Butorides or Syrigma) is unclear at the moment, and molecular studies have until now suffered from a small number of studied taxa. Especially the relationship among the ardeine subfamily is very badly resolved. The arrangement presented here should be considered provisional.

Recent DNA evidence suggests that this family may in fact belong to the Pelecaniformes.[6]

Bare-throated Tiger Heron, Tigrisoma mexicanum
Great Bittern, Botaurus stellaris
Great Blue Heron, Ardea herodias
Great Egret Ardea alba

Subfamily Tigrisomatinae

Subfamily Botaurinae

Subfamily Ardeinae

  • Genus Zeltornis (fossil)
  • Genus Nycticorax - typical night-herons (2 living species, 4 recently extinct; includes Nyctanassa)
  • Genus Nyctanassa - American night-herons (1 living species, 1 recently extinct)
  • Genus Gorsachius - Asian and African night-herons (4 species)
  • Genus Butorides - green-backed herons (3 species; sometimes included in Ardea)
  • Genus Agamia - Agami Heron
  • Genus Pilherodius - Capped Heron
  • Genus Ardeola pond-herons (6 species)
  • Genus Bubulcus - cattle-egrets (1-2 species, sometimes included in Ardea)
  • Genus Proardea (fossil)
  • Genus Ardea - typical herons (11-17 species)
  • Genus Syrigma - Whistling Heron
  • Genus Egretta - typical egrets (7-13 species)
  • Genus undetermined
    • Easter Island Heron, Ardeidae gen. et sp. indet. (prehistoric)

Fossil herons of unresolved affiliations:

  • Calcardea (Paleocene)
  • Xenerodiops (Early Oligocene of Fayyum, Egypt)
  • "Anas" basaltica (Late Oligocene of "Warnsdorf", Czechia)
  • Ardeagradis
  • Proardeola - possibly same as Proardea

Other prehistoric and fossil species are included in the respective genus accounts.

Footnotes

  1. ^ McGill Reporter
  2. ^ "Shitepoke" and "Shikepoke" entries, Webster's Third International Dictionary of the English Language Unabridged, Philip Babcock Gove, Editor in Chief, G. and C. Mirriam Company, 1971 ISBN 0877790019
  3. ^ "Shitepoke" and "Shiterow" entries, Compact Edition of the Oxford English Dictionary, Oxford University Press, 1971, Library of Congress Catalogue Card Number 76-188038
  4. ^ McCracken & Sheldon (1998)
  5. ^ Sheldon et al. (1995, 2000)
  6. ^ A Phylogenomic Study of Birds Reveals Their Evolutionary History. Shannon J. Hackett, et al. Science 320, 1763 (2008).

References

  • McCracken, Kevin G. & Sheldon, Frederick H. (1998): Molecular and osteological heron phylogenies: sources of incongruence. Auk 115: 127–141. DjVu fulltext PDF fulltext
  • Sheldon, Frederick H.; McCracken, Kevin G. & Stuebing, Keeley D. (1995): Phylogenetic relationships of the zigzag heron (Zebrilus undulatus) and white-crested bittern (Tigriornis leucolophus) estimated by DNA-DNA hybridization. Auk 112(3): 672-679. DjVu fulltext PDF fulltext
  • Sheldon, Frederick H.; Jones, Clare E. & McCracken, Kevin G. (2000): Relative Patterns and Rates of Evolution in Heron Nuclear and Mitochondrial DNA. Mol. Biol. Evol. 17(3): 437–450. PDF fulltext

External links

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Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved.  Read more
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Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/.  Read more
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