o. 



OIL 



OAKHAM, in America, 1. 3, r. 848. 

 OBSIDIAN. See Mineralogy, Addenda. 

 OCATAHOOTA, in Geography, a paridi of New 

 Orleans, in Louiilana, refembling in its foil and produce 

 Ouachllla ; which fee. 



OCTOMERIA, in Botany, ox.li;, eight, and fi=pi;, a por- 

 tion, orfiipply, becaufe of the eight maffes of pollen.— Brown 

 in Ait. Hort. Kew. v. 5. 211. — Clafs and order, Gynandrla 

 Monandrla. Nat. Ord. Orchldea. 



Eff. Ch. Lip articulated with a kind of claw which bears 

 the petals. Anther a moveable deciduous lid. Maffes of 



pollen eight. .... . ^ , 



We know not of how many fpecies this genus is compoled. 

 One only occurs in Hort. Kew. 



I. O. gramlmfolla. Grafs-le.aved Oftomeria. Ait. n. i. 

 (Dendrobium graminifoHum ; Willd. Sp. PI. v. 4. 135. 

 Epidendrum graminifoUum ; Linn. Sp. PI. 1 35 3. Helle- 

 borine graminea repens biflora ; Plum. Ic. 171. t. 176. 



f, I.) Stem elongated, bearing one lanceolate leaf, and a 



pair of ftalked flowers. Root creeping.— Native of the 

 Weft Indies; imported by rear admiral Bligh, in 1793. 

 Few botanifts have gathered or e.\amined this plant. Bur- 

 mann, without much fagacity, thought it a Convallarla. 



OGHAM, col. 3, 1. 30, for Dfxtfrt r. Dfxtfrb, and 

 for bfnfdkth r. bfnfdktb. 



OGLETHORPE, 1. 3, containing, with its town Lex- 

 ington, 12,297 inhabitants, of whom the flaves in the county 

 are 5322, and in the town 113. 



OHIO, 1. 8, add — Bradbury, in his " Travels," eftimates 

 the area of the Ohio ftate at 43,860 fquare miles, and its popu- 

 lation at 230,760 fouls ; fo that by this ftatement there was, 

 in 1 8 10, only one inhabitant in one and a half fquare mile, 

 and allowing 640 acres to the fquare mile, one inhabitant in 

 every 900 acres. At the clofe, add — For a later and more 

 correft account of the number of counties and amount of 

 population in this ftate, fee United States. Col. 5, 1. 3 

 from bottom, add — This river derives its waters from an 

 area of 198,464 fquare miles, four times the extent of Eng- 

 land and Wales, the furface of which is fuppofed to be 

 49,450 fquare miles, and comprehended between the parallels 

 of 35 and 43 degrees of latitude. 



Ohio, county of Virginia, 1. 4, r. 8175 inhabitants, of 

 whom 440 were flaves in 1810 ; 1. 6, r. 3682 ; 1. 7, /-. 

 497. Add — Alfo, a townfhip of Alleghany county, in 

 Pennfylvania, having 832 inhabitants. — Alfo, a townfliip of 



Beaver county, in Pennfylvania, having 1 128 inhabitants. 



Alfo, a town of Ohio, in the county of Clermont, having 

 1803 inhabitants. — Alfo, a town of Gallia county, in Ohio, 



having 350 perfons Alfo, a townfliip of Knox county, in 



Indiana territory, 



OIL nf Caraway, 1. i, for C.\nuA r. Carlm. 



O P A 



Oil Creeh. Add — Alfo, a townfliip of Crawford county, 

 in Pennfylvania, having 340 inhabitants. 



OLEA, 1. 4 from bottom, for Calyx r. Corolla. 



OLEFIANT Gas, Chemical Compofitlon of. See Atomic 

 Theory and Carbon. 



OLEIC Acid, in Chemljlry, obtained by Chevreul from 

 a foap made by digefting hog's-lard in potafli ley. When 

 this foap is put into water, a portion was depofited in pearl- 

 coloured fcales, which was the margarate of potajh. ( See 

 Margaric Acld.^ Another portion, confifting of the 

 oleate of polajl:, mixed with fome ma7garate oi -potzih, remain- 

 ed in folution. Thefe two were then feparated, and the 

 oleVc acid obtained in a ftate of purity. Ole'i'c acid when 

 pure is an oily fluid, without tafte or fmell. But moft; 

 commonly it has a rancid odour, and a yellow or brown 

 colour, fomewhat refembling olive-oil. Its fpecific gravity 

 is .899. Sometimes it remains liquid at 35°, though other 

 varieties of it congeal at 43°, or even higher. When con- 

 gealed it cryftallizes in needles. It reddens litmus with 

 great energy. It is infoluble in water, but very foluble in 

 alcohol. It combines readily with the alkalies and earths, 

 forming falts, or rather foaps, none of which poflefs very- 

 remarkable properties. Dr. Thomfon, from Chevreul's ex- 

 periments, eftimates the weight of its atom at 360. It may- 

 be obtained from moft other animal fats as well as hoEr's- 

 lard. ^ 



OLEY, in Geography, a townfliip of Berks county, in 

 Pennfylvania, having 1284 inhabitants. 



OLIVINE. See Olivine, and Mineralogy, Ad- 

 denda. 



O'M, col. 5, 1. 31, for refearches r. refearchers ; I. 42, 

 r. monofyllabic ; 1. 4 from bottom, dele of, and r. one of 

 their. Col. 6, 1. 24,^. compofed of a, &c. 



ONELEG, in Geography, a townfliip of Ohio, in Tuf- 

 carawa, having 610 inhabitants. 



ONONDAGO, 1. 16, r. 25,987, of whom, in 1810, 50 

 were flaves. 



ONSLOW, 1. 3, r. 6669—2299. 



ONTARIO, 1. 3, number of inhabitants in 18 10 was 

 43,032, of whom 212 were flaves. 



OPiETHUS, TouRACO, in Ornithology, a genus of birds 

 of the order of Pics ; the charaftcrs of which are, beak fliort, 

 convex above, rather bent, comprefled laterally, and denticu- 

 lated from the middle to the tip ; noftrils covered with fliort 

 lllky feathers ; feet fimple, with two toes before and two 

 behind. One fpecies of this genus is known, which is a 

 native of Africa, and one of the moft beautiful of the birds 

 that are found in that quarter of the globe. It feeds on 

 fruits, is eafily tamed, and capable, as it is faid, of turning 

 its exterior hinder toe either backwards or forwards. This 

 is the Clculus Parra of the Linnsean fyftem. Shaw. 



OPAL. See Mineralogy, Addenda. 



OPELOUSAS, 



