II H C) 



E. G. I. How many acres are in a piece of land, in the 

 form of a rhombus, whofe diagonals arc 30 and 20 chains ? 

 Anf. 30 acres. 



2 . How many yards of painting are in a reftangle, whofe 

 diagonals, interfering in an angle of 30 , are each 32 



? Anf. 28;.;. 



3. What is the area of a rhomboides, whofe diagonals, 

 making an angle of 6o°, are 30 and 25 feet ? Anf. 3 2^. 7595 

 feet. Hutton's Menfuration. 



Rhombus, Solid, two equal and right cones joined toge- 

 ther at their bafes. 



Rhombus, in Ichthyology, a fpecies of the PleuroneSes ; 

 which fee. See alfo Pleukoxectes Maximus and Turbot, 

 and P. Pajer. 



Rhombus, in Con the name given by the generality 



of authors to a genus of the fhell-fifh, much more 'properly 

 called by fome cylindruf. 



Rhombus, among Surgeons, denotes a fort of bandage of 

 a rhomboidal figure. 



RHON, in indent geography, a river of India, among 

 the people called Gandarii. Steph. Byz. 



RHONDE, in Geography. See Ronde. 



RHONE, a river of France, formed by the union of 

 three fprings, which rife in mount Sufberg, a part of the 

 Grimfell, at the eaftern extremity of the Valais. It pafTes 

 through the lake of Geneva to Seiflel, &c. and thence to 

 Lyons, where it joins the Saone, and after watering Vienne, 

 Valence, Viziers, Avignon, Aries, &c. difcharges itfelf by 

 feveral mouths into the Mediterranean. 



Rhone, Mouths of the, Bouches de Rhone, one of the 

 twelve departments of the S.E. region of France, bounded 

 on the N. by the county of Venaiffin, on the N.E. by the 

 department of the Lower Alps, on the E. by the depart- 

 ment of the Var, on the S. by the Mediterranean, and on 

 the W. by the department of the Gard : 5315 kiliometres 

 in extent, or 269 fquare leagues, and containing a popula- 

 tion of 323,072 perfons. It is divided into three circles or 

 diftri&s, including 26 cantons and 108 communes. The 

 circles are, Marfeilles, having 142,058 inhabitants ; Aix, 

 97,938 ; and Tarafcon, 80,076. According to M. Haffen- 

 fratz, its extent in French leagues is 30 in length and 20 in 

 breadth ; its circles are 5, its cantons are 40, and its po- 

 pulation confifts of 446,643 perfons. It is a portion of 

 Lower Provence, and lies in N. lat. 43° 40'. Its capital is 

 Aix. Its contributions to the land-tax, &c. amounted, in 

 the nth year of the French era, to 3,612,199 fr. ; and its 

 expences, administrative, judiciary, and for public inftruc- 

 tion, to 354, 531 fr. 33 cents. Many of the hills in the 

 northern diftricts are bare rocks, deititute of foil and ver- 

 dure. The chief produftions of the department are grain, 

 wine, filks, olives, fruits, and paftures. It has mines of 

 iron, alum, vitriol, with quarries of marble, &c. Pools 

 and marfhes are difperfed near the coaft. 



Rhone, or Rhone and Loire, one of the eleven departments 

 of the E. region of France, bounded on the N. by the de- 

 partment of the Saone and Loire, on the E. by the depart- 

 ments of the Ain and the Ifere, on the S. by the departments 

 of the Ardeche and the Upper Loire, and on the W. by the 

 departments of the Puy de Dome and the Allier : to the E. 

 it is bounded by the river Rhine, and the Loire pafles nearly 

 through its centre from N. to S. Its extent is 2935 kilio- 

 metres, or 147 fquare leagues, and its population confifts of 

 345,644 perfons. It is divided into 2 circles, 25 cantons, 

 and 261 communes. Its circles are Villefranche, including 

 106,262 inhabitants, and Lyons, having 239,382. Accord- 

 ing to Haflenfratz, its extent in French leagues is 20 in 

 length, and 9 in breadth ; its circles are 2, its cantons 



6 



R H O 



32, and its population is 323,177. It lies in N. lat. 46* 

 between Ain and Loire, and comprehends the provinces for- 

 merly called Lyonnais and Beaujolais. Its capital is Lyons. 

 The plains yield fcanty crops of grain and pafture ; the 

 gentle eminences are covered with vineyards, and the fummits 

 of the mountains are clothed with pines. This department 

 has mines of copper, lead, coal, quarries of marble, free- 

 itone, &c. 



RHOPALA, in Botany, a name altered by Schreber 

 from the Roupala of Aublet, which, being of barbarous 

 origin, and unexplained by the publifher, he contrived, hy 

 the above alteration, to derive from pWx \m, a club, or JlaLe. 

 This may very well apply to the fize and nature of the 

 woody ftem, which' rifes to the height of three or four feet, 

 before it fends off any branches. Vahl and Willdenow have 

 contrived to retain the barbanfm, without adding any thing 

 to thefenfe — Schreb. 62. Brown. Tr. of Linn. Soc. v. ict 

 190. (Roupala; Aubl. Guian. v. 1. 83. Jufl". 79. Lai 

 marck Illuftr. t. 55. Gaertn. fuppl. t. 2 1 7. Rupala ; « Vahl 

 Symb. v. 3. 20." Willd. Sp. PI. v. 1. 5 3 6.)-Clafs and 

 order, Tetrandria Monogynia. Nat. Ord. Proteacez, Jut!'. 

 Brown. 



Gen. Ch. Cal. none. Cor. Petals four, fpatulate, re- 

 gular, concave, recurved at the extremity. Nectary of four 

 glands, feparate or combined, at the bafe of the germen. 

 Stam. Filaments four, fhort, inferted above half way up the 

 petals ; anthers oblong, two-lobed, projecting beyond their 

 recurved extremities. Pi/1. Germen fuperior, ovate, with 

 rudiments of but two feeds ; ftyle awl-fhaped, permanent, 

 the length of the corolla ; ftigma vertical, club-fhaped, un- 

 divided. Perk. Follicle ovate, fomewhat woody, of one cell. 

 Seeds two, bordered, winged at each end, the kernel central. 



EfT. Ch. Calyx none. Petals four, regular, recurved. 

 Stamens inferted into the middle of each petal. Nedtary of 

 four glands. Stigma vertical, club-fhaped. Follicle of one 

 cell. Seeds two, bordered, winged at each end. 



The habit of the genus is arborefcent. Leaves alternate, 

 rarely whorled ; fimple, entire or toothed, rarely pinnate, 

 or ternate, on the fame branch. Spikes axillary, fometimes 

 terminal, racemofe, the flowers in pairs with a fingle brafiea 

 to each pair. 



1. R. montana. (Roupala montana ; Aubl. Guian. v. I. 

 83. t. 32. Lamarck t. ^, Rupala montana ; Willd. n, 1.) 

 -—Leaves alternate, entire, ovate, folded, (hort-pointed, re- 

 ticulated with veins. Spikes axillary, folitary, longer than 

 the leaves. Flower-ftalks, petals and germen clothed with 

 rufty down — Native of the Serpent Mountain in Guiana, 

 flowering in Auguft. Sublet. A fmall tree, feven or eight 

 feet high ; its trunk three or four feet. Bart wrinkled and 

 cracked, whitifh, as well as the wood. Both exhale, when 

 cut, a ftrong fetid fcent, like that of the ferpents of the 

 fame country. Leaves fmooth, of a firm dry texture, about 

 three inches long. Footftalks an inch long, inflated at the 

 bafe. Flowers about eight or ten alternate feffile pahs, in 

 each hxjpiie. 



2. R. media. Brown n. 2 — Leaves alternate, entire, 

 ovate, flat, pointed, running down the footftalk, with de- 

 preffed veins. Clufters axillary, folitary, longer than the 

 leaves. Partial flower-ftalks and petals fomewhat hairy. 

 Germen downy. — Gathered in the fame country by Von 

 Rohr, who fent fpecimens to fir Jofeph Banks. This feems 

 very nearly related to the foregoincr. 



3. R. nitida. Br. n. 3. (Repala nitida ; Rudge Guian. 

 v. 1. 26. t. 39.)— Leaves alternate, entire, elliptical, (hort- 

 pointed, flat. Clufters axillary," folitary, about the length 

 of the leaves. Partial flower-ftalks, petals and germen 

 fmooth.— Gathered by Jofeph Martin in Guiana. Brown. 



4- R- 



