11 A V 



that each Joiind below doulilc F refemblL-s that of an or- 

 gan-pipe ill flow note;., more than the tranfient tone of a 

 llriiig. 



Roufl'eau very julUy obferves, that almoft all iirflrumcnts 

 aiv limited in their compafs below, except harps and in- 

 itriiments with keys. Tlie violoncello can go no lower than 

 double C, its 4th llring, nor the violin below G. The flute 

 and haulbois defcend only to U and C. But the notes in 

 alt. have been extended in the acute to founds that are 

 feldom in tune, and never pleafing. Like rapid notes of 

 difficult execution, they y(«-/»7'iif, and the performer's dex- 

 terity is applauded ; but neither the harmony nor the me- 

 lody of very high or rapid founds can excite rapture like 

 thofe of moderate quicknefs, when produced with feeling 

 and expreffion, in the middle of the fcale. 



RAVALSHE, in Geography, a town of Sweden, in Weil 

 Gothland ; 24 miles N.W. of Uddevalla. 



RAVANA, in Hindoo Mythology. See Ravena. 



RAVANAK, in Geography, a town of European Tur- 

 key, in Macedonia ; 16 miles E.S.E. of Saloniki. 



RAUAND, a town of Perfia, in the province of Ker- 

 man ; 105 miles E. of Sirgian. 



RAVA-POU, in Botany, Rheede Hort. Malab. v. 4. 

 99. t. 48, a plant erroneoufly cited by Linnxus for his 

 very different NyBanthes hirfuta. See Guettarda Spedofa. 



RAUCA Avis, in Ornithology, the name of a bird de- 

 fcribed by Nieremberg, as common about the lakes and 

 rivers of America, and of the kingfilher kind, but nearly 

 as large as a duck, and black on the crown, and white on 

 the bread and belly. Its neck is naturally very long in pro- 

 portion to its body, yet it can occafionally contraft and 

 Shorten it in a very wonderful manner. It is a native of 

 Mexico, and is elleemed very good for the table. Mr. 

 Ray has placed this among the birds, the accounts of which 

 he is diftrultful of. 



RAUCH, in Geography, a town of Germany, in the 

 lordOiip of Schwarzenberg ; i o miles S. W. of Scheinfeld. 



RAUCHENEGG, a town of Auftria ; 2 miles W. 

 of Baden. 



RAUCHT, a town of Ruflia, in the government of 

 Viborg, near lake Ladoga ; 44 miles S.E. of Viborg. 



RAUDANAGUR, a tovvn of Bengal ; 30 miles E. of 

 Ranigur. 



RAUDEN, a town ©f PrufTia, in the palatinate of Culm ; 

 10 miles N.E. of Culm. — Alfo, a town of Silefia, in the 

 principality of Ratibor ; 12 miles N.E. of Ratibor. 



RAUDNIZ, a town of Bohemia, in the circle of 

 Schlan ; iz miles N.N.E. of Schlan. — Alfo, a town of 

 Bohemia, in the circle of Cin-udim ; 16 miles N.N.W. of 

 Chrudim. 



RAUDRI, a name of the Hindoo goddefs Parvati, 

 confort of Siva, the dellroying power. In this charafter 

 (he may be confidered us his Sakti, or energy in his form of 

 Rudra, or Fate. Rudri, and Rudrani, are other modes of 

 writing this name of the goddefs in her averging charafter, 

 in which llie does not apparently differ much from her at- 

 tributes, as Sakti of Mahaiala ; under which name, and 

 the others occuring in this article, dillinguiflied by italics, 

 farther and fufficient information may be fought. See alfo 

 Trisakti-devi, and Tamas[. 



RAUD TEN, in Geography, a town of Silefia, in the 

 principality of Wohlau ; 18 miles N.W. of Wohlau. N. 

 lat. 51'^ 30'. E. long. 16^ 15'. 



RAVEL Bread, a fort of bread, called alfo blackivhytlof, 

 as being of a middle finenefs betwixt white and brown. 



RAVELIN, in Fortification, was anciently a flat baftion, 

 placed in the middle of a curtain. 



II A V 



Ravelin is now a detached work, compofed only of two 

 facei, which make a faliant angle, without and fometimes 

 with flanks ; and raifcd before the curt; in on the counter- 

 fcarp of the place; ferving to cover it and the joining flanks 

 from the dirett fire of an enemy. 



A ravelin is a triangular work, refembling the point of 

 a baftion, with the flanks cut off. (See Plate V. Fortification, 

 jig. 4. lit. i i i. &c. ) Its ufe before a curtain is, to cover the 

 oppofite flanks of the two next liaflions. It is ufcd alfo to 

 cover a bridge or a gate, and is always placed without the 

 moat. 



What the engineers call a ravelin, the foldiers generally 

 call a demi-lune, or half-moon. Sec Demi-lune. 



There are alfo double ravelins, which ferve to defend each 

 other. They are faid to be double when they are joined by 

 a curtain. 



Ravehns, or half-moons, are conftrucled by fetting oft' 

 50 toifes from the re-entering angle O of the counterlcarp 

 {Plate VII. Fortification, Jig. 4.) on the capital O I- of the 

 ravelin, or on the perpendicular produced, and from the 

 point L drawing lines to the fhoulders A, B ; vvhofe parts 

 L M, L N, terminated by the countcrfearp, will be the 

 faces M O, O N, the femi-gprges of the ravelin recjuired. 

 Others will have the faces of the ravelin to terminate on 

 thofe of the baflions within three toifes of the llioulders, in 

 which cafe the ravehns cover the flanks better than the 

 othe/s. The ditch before the ravelin is 12 toifes, and its 

 counterfcarp parallel to the faces of the ravelins, and made 

 in a circular arc before the faliant angle. When the ravelins 

 are made with flasks, the faces fhould terminate thofe of the 

 baftions, at leaft 5 toifes from the flioulders. Thcfe flanks 

 are made by fetting off 10 tpites from the extremities of the 

 faces, and from the points thus determined, the flanks are 

 drawn parallel to the capital of the ravelin. When redoubts, 

 or keeps, are formed in the ravelin, this is done by fettinu- 

 off 16 toifes from the extremities of the faces, on the femi- 

 gorges from N to b, and from M to a ; and from the points 

 b, a, the faces are drawn parallel to thofe of the ravelin : the 

 ditch before this redoubt is 6 toifes, and its counterfcarp 

 parallel to the faces. This work fhould be covered in the 

 faces by a wall, a foot or two thick, furnifhed with loop- 

 holes for the mufketry to tire through ; and it will ferve to 

 fecure a retreat for the troops who defend the ravehn ; they 

 may thus prevent the enemy from making a lodgment in 

 the outward part of the ravelin, or at leaft greatly obllruft 

 their attempts for this purpofe. Nor can they be drove 

 from this place, until the enemy has erefted a battery, and 

 brought cannon on the ravelin to batter the redoubt. When 

 the ccunterguard ^which fee) is placed before the ravelin, 40 

 toifes are fet off on the capital of the ravelin from its faliant 

 angle to the faliant angle of the counterguard, and 10 on 

 the counterfcarp of the ditch. For the conilrudtion of 

 crown-works before the ravelin, fee HoRX-TOor/f. Within 

 the ravelin are conftrudled a rampart of about 16 or 20 

 yards, and a parapet of about 6 yards : ramps are alfo an- 

 nexed in the flope of a rampart, and a barbet, when it is pro- 

 per, is conflrufted in a faliant angle. In wet ditches, where 

 the troops pafs from the town to the ravelin in boats, it is 

 proper to make, in the gorge of the ravelin, a kind of har- 

 bour, where the boats may be covered from the fire of the 

 enemy. In dry foffes, there fhould be ramps or flairs in 

 the gorge of the ravelin, to preforve a free communication, 

 if the bridges fhould be broken down by the enemy's fhot. 

 The celebrated general Coehorn, in the ravelins which he 

 built at Bergen-op-zoom, contrived a very good defence 

 for the covered way before the faces of the baftions, by 

 making retired flanks in the brcilts of the ravelin, where 



one 



