IUC 



K1F 



due. From the properties of the watery 

 extract, enumerated by that laborious 

 chemist, we may infer, with some proba- 

 bility, that it consists chiefly of an ex- 

 tractive and bitter principle, and that it 

 contains some tannin. A small quantity 

 of greenish yellow, resinous matter, seems 

 also to be present. Scheele separated 

 from the root about one-sixth of its 

 weight of oxalate of lime. But this salt is 

 not aken up by water See MATERIA 

 MEBICA, and PHARMACY. 



RHUMB, in navigation, a verticle cir- 

 cle of any given place, or the intersection 

 of such a circle with the horizon ; in 

 which last sense rhumb is the same with 

 a point of the compass. 



RHUMB line, is also used for the line 

 which a ship describes when sailing in the 

 same collateral point of the compass, or 

 oblique to the meridians. 



RHUS, in botany, sumach, a genus of" 

 the Pentandria Trigynia class and order. 

 Natural order of Du'mosse. Terebmtarere, 

 Jussieu. Essential character : calyx five- 

 parted ; petals five ; berry one-seeded. 

 There are thirty-four species. 



RIBES, in botany, the currant and goose- 

 berry, a genus ot the Pentandria Monogy- 

 nia class and order. Natural order of 

 Pornacex. Cacti, Jussieu. Essential 

 character: petals five, inserted with the 

 stamens into the calyx ; style bifid; berry 

 many seeded, inferior. There are seven- 

 teen species, -viz. ten of the currant, and 

 seven of the gooseberry ; all these shrubs 

 are too well known to'need a particular 

 description in this work. 



RICCIA, in botany, so named in honour 

 of Pietro Francisco Riccio ; a genus of the 

 Cryptogamia Hepaticx class and order. 

 Generic character: male, flowers sessile 

 on the surface of the frond ; calyx and 

 corolla none : female, flowers on the 

 same, or, according to Micheli, on a dis- 

 tinct plant ; calyx none, except a vesicu- 

 lar cavity, within the substance of the leaf; 

 corolla none. Linnaeus has five species, 

 natives of Europe. Withering reckons 

 the same number, all natives of Britain. 



RICHARDU, in botany, so named 

 from Richardson ; a genus of the Hexan- 

 dria Monogynia class and order. Natu- 

 ral order of Sleliatze. Rubiacex, Jussieu. 

 Essential character : calyx six-parted ; 

 corolla one-petalled, sub-cylindric; seeds 

 three There is only one species, viz. R. 

 scabra, a native of Vera Cruz. 



RICHERIA. in botany, so named in 

 memory of Pierre Richer de Belleval, 

 Professor of Botany at Montpelier ; age- 

 uus of the Dioecia Pentandria class and 



order. Essential character : capsule cor- 

 ticaie, six-valved, tmee Ct 'Id ; seeds so- 

 litary, pendulous, below the tip of the 

 columclla ; s'.yle tri!M. There is but one 

 species, ri~. li grand!?, a naiive of Monl- 

 serrat. 



RICINUS, in botany, a genus of the 

 Monoeeia Monadelphia class and order. 

 Natural order of Tricoccse. Euphorbia;, 

 Jussieu. Essential character: calyx five- 

 parted; corolla none: male, stamens nu- 

 merous : female, styles three, biiid ; cap- 

 sule three-celled ; seed one. There are 

 six species. 



RICOH A, in botany, a genus of the 

 Tetradynamia Silkjuosa class and order. 

 Natural order of Siliquosae, or Cruci for- 

 mes. Crur.iferae, Jussieu. Essential cha- 

 racter : silique one-celled, oblong, com- 

 pressed, with flat valves. There* is but 

 one species, viz. R. aegyptiaca, Egyptian 

 ricotia. 



RIDE, in the sea-language, is a term 

 variously applied : thus, a ship is said to 

 ride, when her anchors hold her fast, so 

 th.-it she does not drive by the force either 

 of the wind or tide. A ship is said to ride 

 across, when she rides with her fore and 

 main yards hoisied tip to the hounds, and 

 both yards and arms topped alike. She 

 is said to ride well, when she is built so 

 as not to over-beat herself in a head sea, 

 the waves over-raking her from stem to 

 stern. To ride athwart, is to ride with 

 her side to the tide. To ride betwixt 

 wind and tide, is to ride so as the wind 

 hns equal force over her one way, and the 

 tide the contrary way. If the wind hns 

 more power over the ship than the tide, 

 she is said to ride wind-road, or to ride a 

 great, wind. And she is said to ride a 

 portoise, when the yards of a ship are 

 struck down upon the deck. 



RIDER, is a schedule, or small piece 

 of parchment, added to some part of a re- 

 cord ; as when, on the third reading of a 

 bill in Parliament, a new clause is added, 

 that is tacked to the bill, on a separate 

 piece of parchment, and is called a rider. 



R1I)1N"G unnrd, with dangerous and 

 unusual weapons, is an offence at com- 

 mon la T ,v. 



RIFLE, a fire-arm, which has the inside 

 of its barrel cut with from three to nin 

 or ten spiral grooves, so as to make it re- 

 semble a female screw, varying 1 from a 

 common screw only in this, that its 

 grooves or rifles are less deflected, and 

 approach more to a right line ; it being 

 now usual for the grooves with which the 

 best rifled barrels are cut, to take about 

 one whole turn in a length of thirty incti- 



