Naturalist John Hill Named Sea Horse Constellation Hippocampus in 1754

Summary: English naturalist John Hill named sea horse constellation Hippocampus in his 1754 astronomical dictionary, Urania, or, A Compleat View of the Heavens.

John Hill's Hippocampus the Sea Horse constellation (center-right) inhabits the southern celestial hemisphere's first quadrant (SQ1), in the neighborhood of Cetus the Sea Monster, Eridanus the River, Orion the Hunter and Taurus the Bull, and shares the quadrant with two other Hill-invented constellations, Limax the Slug (upper right) and Testudo the Tortoise (lower left): Ultima Thulean, CC BY SA 4.0 International, via Wikimedia Commons

Eighteenth-century English apothecary, naturalist and writer John Hill introduced Hippocampus the Sea Horse constellation in his astronomical dictionary, Urania, or, A Compleat View of the Heavens, published in 1754.

Hill (1714-Nov. 21, 1775) introduced the maritimely equine constellation with the standard epithet that he uniformly applied to all 15 new constellations in Urania. "A conſtellation offered to the aſtronomical world," he announced, adding "and compoſed of certain conſpicuous and unformed ſtars under the feet of the conſtellation Taurus."

Hill extolled the saltwater fish that inspired his constellatory discovery. "The creature from which it takes its name is one of the moſt ſingular animals in the world, it is frequently met with dried in the collections of the curious, and its long and narrow head, its curled body, and bent neck make it very remarkable. It is a fiſh of the Syngnathus, or Needle Fiſh kind. Moſt of the naturaliſts have named it, and it is described and figured in the hiſtory of animals, publiſhed ſome little time ſince by the author of theſe obſervations."

Four constellations neighbor Hippocampus the Sea Horse, according to Hill's design. Cetus the Sea Monster, Eridanus the River, Orion the Hunter and Taurus the Bull surround Hippocampus. The sea horse's head associates with Cetus and Eridanus. "The head of the Hippocamp is pointed at the breaſt of the Whale, and comes between the head of that monſter and Eridanus."

The celestial river joins with Taurus in considering the Sea Horse. The Bull's fore feet occur "over the hinder part of its body, and the Eridanus runs in ſome degree parallel under it."

The vertically swimming, equinely reminiscent fish indicates Orion. "Its tail points at the ſide of Orion, and comes near to the lion's ſkin he holds up in his left hand."

Hill noted the spaciousness of the space assigned to the Sea Horse and the number and conspicuousness of its starry occupants. "It is of ſome conſiderable extent in the heavens, and, for the ſpace it occupies, is ornamented with no inconſiderable number of ſtars, and theſe are all happily diſpoſed, and ſome of them ſufficiently conſpicuous."

Also, the size of the constellatory figure does not necessitate proportionalizing the constellation's territory. "There might be an objection ſtarted againſt the making ſo ſmall a fiſh as the Hippocamp extend over ſo large a ſpace of the heavens; but there is an example, very near at hand, that proportion has not been obſerved between the ſeveral figures. When we ſee the paw or fin of the Whale cover the whole breadth of the river Eridanus, we are not to except againſt making the little Hippocamp longer than the club of the Great Oron."

Hill tallied Hippocampus the Sea Horse's "conſiderable ſtars" at 21, "many of them very conſpicuous." He identified "their exact places and ſituations . . . in the figure of the conſtellation."

Four small, yet distinct stars pair in the Sea Horse's head to express "the upper part of the head" and to accentuate "the end of the ſnout."

Six stars define the "riſing" and "deſcending out-line" of the bend in the Sea Horse's neck. The "upper out-line" of the rising neck accommodates two large stars, with "the hinder one the larger and brighter." Four stars mark the bend's descent with placements of three near the outline and one in the body. One of the trio is lower than its companions and agrees with "the ſingle ſtar" in brightness and largeness.

Near the outline in the bend's lower part three stars distinguish themselves. The largest of the three is distant from the other two, which are "ſmaller, and near to one another." Beyond this trio, also in the outline, another trio clusters close together, again with one that "is large, and two are ſmaller." Beyond the clustered trio, "near the upper out-line, are two very conſpicuous."

The last three of the Sea Horse's 21 stars define the tail. This last trio separates into a single star at the tail's extremity and "two a little diſtant, one in the upper, and the other in the lower out-line."

Hill ended his tour of Hippocampus with an expression of satisfaction. "By theſe the whole figure is very well deſcribed."

Nine of Hippocampus the Sea Horse's 21 stars are identified by David Harper, once an astronomer specializing in celestial mechanics and positional astronomy but now a genome researcher, and his wife, astronomer L. (Lynne) M. Stockman, in "Hippocampus -- The Sea Horse," posted on their Obliquity website. Two of the nine reside in Cetus the Sea Monster: 94 Ceti (abbreviated 94 Cet) and Kappa1 Cet (κ1 Cet). Eridanus the River contributes six of the nine stars: 17 Eridani (abbreviated 17 Eri), 24 Eri, 30 Eri, 32 Eri, 35 Eri and 45 Eri. Taurus the Bull lends one star to the marine constellation: 10 Tauri (abbreviated 10 Tau).

Hippocampus the Sea Horse occupies the southern celestial hemisphere's first quadrant (SQ1). The celestial Sea Horse shares the quadrant with two other Hill-invented constellations, Limax the Slug and Testudo the Tortoise.

The International Astronomical Union (IAU) has not recognized Hippocampus as an official constellation. Accordingly, Hippocampus does not appear on the list of 88 IAU-approved constellations. Although absent from Earthly lists and sky carts, Hippocampus the Sea Horse still retains its celestial presence in Earth's nightly skies.

John Hill's Hippocampus the Sea Horse constellation emerges from conspicuous, unformed stars near Taurus the Bull in the southern celestial hemisphere's first quadrant (SQ1); John Hill, Urania, or, A Compleat View of the Heavens (1754), between third and fourth of four pages on "Bull, Taurus": Public Domain, via Google Books Read for Free

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

John Hill's Hippocampus the Sea Horse constellation (center-right) inhabits the southern celestial hemisphere's first quadrant (SQ1), in the neighborhood of Cetus the Sea Monster, Eridanus the River, Orion the Hunter and Taurus the Bull, and shares the quadrant with two other Hill-invented constellations, Limax the Slug (upper right) and Testudo the Tortoise (lower left): Ultima Thulean, CC BY SA 4.0 International, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Southern_Hemisphere_Hill's_Constellations.png

John Hill's Hippocampus the Sea Horse constellation emerges from conspicuous, unformed stars near Taurus the Bull in the southern celestial hemisphere's first quadrant (SQ1); John Hill, Urania, or, A Compleat View of the Heavens (1754), between third and fourth of four pages on "Bull, Taurus": Public Domain, via Google Books Read for Free @ https://www.google.com/books/edition/Urania_or_a_compleat_view_of_the_Heavens/n_ReAAAAcAAJ?hl=en&gbpv=1; Ultima Thulean, CC BY SA 4.0 International, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Dentalium_Constellation.jpg

For further information:

Harper, David; and L. (Lynne) M. Stockman. "Hippocampus -- The Sea Horse. Unofficial Abbreviation: Hip. Genitive: Hippocampi. Origin: John Hill." Obliquity > Sky Eye > The Constellations > Extinct Constellations.
Available @ https://www.obliquity.com/skyeye/88const/Hip.html

Hill, John. "Hippocampus." Urania, or, A Compleat View of the Heavens, Containing the Antient and Modern Astronomy, in Form of a Dictionary. London: T. Gardner, M.DCC.LIV [1754].
Available via Google Books @ https://www.google.com/books/edition/_/lzigAAAAMAAJ?hl=en
Available via Internet Archive @ https://archive.org/details/bub_gb_lzigAAAAMAAJ/page/n240/mode/1up

Hill, John. Urania, or, A Compleat View of the Heavens, Containing the Antient and Modern Astronomy, in Form of a Dictionary. London: T. Gardner, M.DCC.LIV [1754].
Available via Google Books @ https://www.google.com/books/edition/_/lzigAAAAMAAJ?hl=en
Available via Internet Archive @ https://archive.org/details/bub_gb_lzigAAAAMAAJ/

Hill, John, M.D. [Urania]. A New Astronomical Dictionary, or, A Compleat View of the Heavens Containing Antient and Modern Astronomy Illustrated with a Great Number of Figures. London: T. Gardner, MDCCLXVIII [1768].
Available via Internet Archive @ https://archive.org/details/bim_eighteenth-century_urania-a-new-astronom_hill-john-m-d-calli_1768/

Marriner, Derdriu. "English Naturalist John Hill Introduced 15 Constellations in 1754." Earth and Space News. Wednesday, Aug. 2, 2023.
Available @ https://earth-and-space-news.blogspot.com/2023/08/english-naturalist-john-hill-introduced.html

Marriner, Derdriu. "English Naturalist John Hill Named Bufo the Toad Constellation in 1754." Earth and Space News. Wednesday, Aug. 23, 2023.
Available @ https://earth-and-space-news.blogspot.com/2023/08/english-naturalist-john-hill-named-bufo.html

Marriner, Derdriu. "English Naturalist John Hill Named Eel Constellation Anguilla in 1754." Earth and Space News. Wednesday, Aug. 9, 2023.
Available @ https://earth-and-space-news.blogspot.com/2023/08/english-naturalist-john-hill-named-eel.html

Marriner, Derdriu. "English Naturalist John Hill Named Spider Constellation Aranea in 1754." Earth and Space News. Wednesday, Aug. 16, 2023.
Available @ https://earth-and-space-news.blogspot.com/2023/08/english-naturalist-john-hill-named.html

Marriner, Derdriu. "Naturalist John Hill Named Shellfish Constellation Gryphites in 1754." Earth and Space News. Wednesday, Sep. 13, 2013.
Available @ https://earth-and-space-news.blogspot.com/2023/09/naturalist-john-hill-named-shellfish.html

Marriner, Derdriu. "Naturalist John Hill Named Tooth Shell Constellation Dentalium in 1754." Earth and Space News. Wednesday, Aug. 30, 2023.
Available @ https://earth-and-space-news.blogspot.com/2023/08/naturalist-john-hill-named-tooth-shell.html

Sassarini, Iacopo. "κ1 Ceti (kappa1 Ceti)." The Sky Live > Constellations > Cetus.
Available @ https://theskylive.com/sky/stars/kappa1-ceti-star

Sassarini, Iacopo. "94 Ceti." The Sky Live > Constellations > Cetus.
Available @ https://theskylive.com/sky/stars/94-ceti-star

Sassarini, Iacopo. "17 Eridani." The Sky Live > Constellations > Eridanus.
Available @ https://theskylive.com/sky/stars/17-eridani-star

Sassarini, Iacopo. "24 Eridani." The Sky Live > Constellations > Eridanus.
Available @ https://theskylive.com/sky/stars/17-eridani-star

Sassarini, Iacopo. "30 Eridani." The Sky Live > Constellations > Eridanus.
Available @ https://theskylive.com/sky/stars/30-eridani-star

Sassarini, Iacopo. "32 Eridani." The Sky Live > Constellations > Eridanus.
Available @ https://theskylive.com/sky/stars/32-eridani-star

Sassarini, Iacopo. "35 Eridani." The Sky Live > Constellations > Eridanus.
Available @ https://theskylive.com/sky/stars/35-eridani-star

Sassarini, Iacopo. "45 Eridani." The Sky Live > Constellations > Eridanus.
Available @ https://theskylive.com/sky/stars/45-eridani-star

Sassarini, Iacopo. "10 Tau." The Sky Live > Constellations > Taurus.
Available @ https://theskylive.com/sky/stars/10-tauri-star