o.
O R P
O X L
OAK (Cycl) — Oak of-Jerufalem, the Englifh name of a genus of plants, called by botanifts Cbenopoiium, See the article Chenopodium, Suppl. Poifon-OAK, a name fometimes given to the7W- codendronoi botanifts. Seethe article Toxicodendron, Suppl.
OAT-grafs, in botany. See the article Grass, Append.
OBELIAS, among the anticnts, a kind of fmall cakes, which
' Were toafted on little fpits, and ferved to table as a defert to be
' eaten dipped in fwcet wine, called Paffum. Pitijc. in voc.
OBELLlSCOTHECA, the name given by Vaillant to a genus of plants, called by Linnxus Rudbcckia. See the article Rud- beckia, Append.
OBTUSE (Cycl.) — OsTUSE-angular Seclion of a Cone, a name given to the hyperbola by antient geometricians, becaufe they confidered it only in fuch a cone, whofe fedtion by the axis is a triangle, obtufe-angkd at the vertex.
OCK.HAM, or Ocham, See the article Oakham, Cycl. . OCTAETIS, in natural hiftory, a name given by Linnaus, and many other authors, to a kind of ftar-fifh of the aftro- phyte clafs, the rays of which are eight in number, where they firft part from the body, but foon divide into many more.
OIL-bcetle, the Englifh name of a genus of infeSs, called by Dr. Hill Meloe. See the article Meloe, Append.
OILY-grain, the name by which fome call the Sejhmttm, of botanical authors. See the article Sessamum, Append.
OLD-wife-f/b, the name by which a l'peciesof Ballijles is cal- led in feveral of our plantations. See the article Ballistes, Suppl.
OlD-wife is alfo a name given to the wraffe, a fpecies of La- brus. See the article Lab rus, Suppl.
OLIVE (Suppl.) — Spurge-OtiVE, a name fometimes given to the fbymeUa of botanifts. See the article Thy- meljea, Suppl. ■
Ifild-OhlVE, the Englilh name of a diftinct genus of plants, called by Linnaeus Elaagnus. See the article Eljeagnus, Suppl.
fP'ild-OLlVE of Barbadoes, a name by which fome call the Bont'ia, a diftincl genus of plants. See the article Bontia, Suppl.
ONK-berry, a name by which the hcrba Paris is fometimes called. See the article Herb a Paris, Suppl.
OuE-blade, crOuE-leaf, names fometimes given to the Smi- lax of botanical writers. See the article Smilax, Suppl.
ONlON(SuppL)— Sea-Oxion, a name by which the Scillaoi botanifts is fometimes called. See the article Scilla, Append.
OPERCULUM, in the hiftory of fhell-fifh, denotes the car- tilaginous cover, with which nature has furnifhed the mouths of the univalve water-fiiells ; for as to the land ones, they have only a vifcid liquor to fupply the place of an Oper- culum.
ORACH, a name by which the Cbenopodium of botanical au- thors is fometimes called. See the article Chenopodium, Suppl.
ORANGE-Afti/, the name of a fpecies of Mint. See the articles Mentha and Mint, Suppl.
Mock-O&AnGE, a name fometimes given to the Syringa, or pipe-tree. See the article Syringa, Suppl.
ORELLANA, in botany, a name given to a fpecies of Mi- ' tella. See the article MlTELL A, Suppl.
ORPHEUS. This iilh has been called Orphos, Orphus, and Cernua, by different writers. It is a fpecies of Sparus, with the tail not forked, and with a black fpot near it. See the articles Spa rus and Orpheus, Suppl.
ORPINE, in botany, the Englifh name of a genus of plants, known among botanical writers by that of Telephium. See the article Telephium, Suppl.
BaJlard-OupiNii, a name given to two diftinct genufes of plants, called by botanifts Anacampferos and Andracbne. See the articles Akacampseros, and Andrachne, Suppl.
ORRERY, an aftronomical inftrument, or rather machine for reprefenting the motions and various appearances of the pla- nets ; and hence, with greater propriety, called Planetarium. See the article Ppanetarium, Append. The reafon of its being called an Orrery, was this : Mr. Rowley, a mathematical inftrument - maker, havino- goc one from Mr. George Graham, the original inventor, °to be fent abroad with fome of his own inftruments, he copied it and made the firft for the Earl of Orrery. Sir Richard Steel' who knew nothing of Mr. Graham's machine, thinking to do juftice to the full encourager, as well as to the inventor of fuch a curious inftrument, called it an Orrery, an d gave Mr. Rowley the praife due to Mr. Graham. DeftiguTiers Experiment. Phil. vol. i. p. 430.
Since that time Orreries have been much in vogue, and exe- cuted in the molt ornamental manner.
ORTHOCEROS, the fame as Orthocerites . See the atticle Orthocerites, Suppl.
ORYZA, Rice, in botany, the name of a genus of plants of which we know only one fpecies : The characters are thefe - The cup is a glume, compofed of two valves, with a fin»]e flower ; it is very fmall, and the valves are acuminated, and nearly equal in fize ; the flower is alfo compofed of two ob- tufe and permanent valves ; the nectarium confifts of two very fmall deciduous leaves ; the ftamiha are fix capillary filaments of the length of the flower ; the antherae are bifid at thebafe • the germen of the piftil is of a turbinated figure ; the ftyles arc two, capillary, and reflex ; the ftigmata are plumofe • there is no pericarpium ; the feed ii fmgle, lame, O blono' obtufe, and comprefled. Linnai Gen. Plant, p. 152. "*
OSCULATION in geometry, is ufed for the contadt between any given curve and its ofculatory circle ; that is, the circle of the fame curvature with the given curve. See the article Curvature, Append.
OSCULATORY-aWf, in geometry, is ufed chiefly by fore™ mathematicians, for the circle of curvature.; that is, the cir- cle having the fame curvature with any curve at any »iven point. Seethe article Curvature, Append. °
OscuLATORY-Puraio/tf. See tlie article Parabova, Append.
Oscul at ory -point, the point of contact between a curve and its ofculatory circle. See the articleCuRVATURE, Append.
OSIER, the Englifh name for the willow with very loiio- arid narrow leaves. See the article Salix, Suppl.
OTARDES, in ornithology. See the article Otis, Suppl.
OUZEL, or ici'^-OuZEL, the Englifh name of the black Tardus, with a white ring round its neck. See the article Turdus, Suppl.
OWL, in ornithology, a large genus of birds, for the cha- racters of which fee the article Strix, Suppl.
Grey-Ov/L. See the article Ulula, Suppl.
Great-white Owl., a very large fpecies, nearly equal to a goofe in bignels ; of a beautiful bright white all over, only iprink- led, as it were, with little fpots of a blackilh colour. The other fpecies are : 1. The black and white horned Owl 2. The lefler horned Owl. 3. The yellow Owl. 4. The hazel-eyed Owl. 5. The yellow-eyed Owl. 6. The Owl with a variegated tail. 7. The little Owl. 8. The common brown Owl, or Jay-CM. 9. The Scops. 1 0. The German horned Owl. 11. 1 he church Owl, or lefler barn Owl. 1 2. The white-beaked Owl. 13. The yellow-beaked American Owl. 14. The Jacurutu. Hill, Hifl. Anim. p. „q feq. F y
OX-eye, in botany, the Engliih name of a genus of plants, called by botanifts Buphthalmum. See the article Buph- thalmum, Suppl.
Ox-eye-daify, a name fometimes given to the Leiicanthemum of botanmcal writers. See the article Leucanthemum Suppl. '
Ox-lip, a name by which the Primula vcris, prirnrofp, or prime rofe, is fometimes called. See the article Primula, Suppl.
