R OA

490

RO A

tainly unfit for the purposes of life ; yet, by remaining for sometime at rest, all the tVeulencies subside, and the water becomessufficiently pure and potable.

RlVlNA, American Nightshade ; in botany, a genus ofthe inonogynia order, and tetrandria class of plants. Caiyx four-leaved, coloured, permanent; leaflet oblong-egged and obtuse ;no corolla ; berry globular, sitting on fhe green reflected calyx,one-celled with an incurved point; seed one, lens-form. There arefour species.

R1 VO LI, a town of France , in the department of the Po, andlate province of Piedmont, 9 miles W. of Turin .

Rivoli, or Rtvot.o, a town of Italy , in the department of theMincio, and late duchy of Verona ; 20 miles N. W. of Verona .

RlXDOLf.AR, a German coin, worth about four shillings andsix-pence sterling.

ROA, a strong town of Spain , in Old Castile; will) a citadel,lOmiles'S. W. of Aranda, and 70 N. of Madrid .

ROACH, in ichthyology. See CyrRixcs.

ROAD , an open wav, or public thoroughfare, which forms acommunication between two distant places. Roads being fre-quently disfigured, and otherwise injured bv the deep ruts whichare necessarily made by' the continual passing and repassing ofnarrow wheel-carriages; various machines have been contrived,with a view to facilitate the repairing of highways, and to fill upsuch excavations.—From these, we shall first communicate theRoad Harrow, invented by Mr. Harriott, to whom the Societyfor the Encouragement of Arts, Sic. in 17S9, voted a reward often guineas.—As this machine may not only be employed withgreat advantage, by the surveyors of public roads, but will also befound very' serviceable in repairing and improving the private ways,or avenues, belonging to manors, we have given a view of it inPlate CLV, fig. 8. The head of the harrow is three feet widefrom one side of the bar to the other, externally. These bars arefour inches square ; five feet long ; and, to prevent them frombeing split, they are contrived lengthwise, instead of being in atransverse direction. The mould-boards are four feet two inchesin length, ten inches in depth, and two in thickness : they extendeleven inches beyond the bars, in order that the stones (which arebrought to the surface by the teeth of the harrow) may be drawninto a smaller compass. These mould-boards are, farther, shodwith an-iron-bar, and lined with a plate of the same metal, to theheight of the spot where they are marked black, in the figure abovementioned ; and such parts ofthis delineation, as are represented ofa deeper colour, distinguish the iron from the wood-work. Theteeth are one foot in length from the inferior side of the bars totheir points, which ought to be steeled: they are 11 inch square,and are fixed by means of strong nuts and screws, with collars bothon the upper and lower side of such bars. Mr. Harriott’s road-harrow is drawn by two horses abreast: the outside animal is ledby a boy on that quarter ; while the other horse walks in the pro-per patli, and a man keeps the harrow steady by the handies:consequently they take one inside and one outside "quarter in theirprogress, and the remaining two quarters in their return. By thisexcellent machine, a man, boy, and two horses, may with ease re-pair three miles in length, in one day ; harrowing down the quar-ters, and drawing the stones together, which are dropped into theruts, by means of the mould-boards, in a more effectual mannerthan if they were stubbed in by a man. Lastly, the work is per-formed not only more expeditiously, but also at one-tenth part ofthe expence incurred, when the roads are repaired by manual la-bour. Of all the people in the world the Romans took the mostpains in forming roads ; and the labour and expences they were atin rendering them spacious, firm, straight, and smooth, are incre-dible. They usually strengthened the ground by ramming it, lay-ing it with flints, pebbles, or sands, and sometimes with a lining ofmasonry, rubbish, bricks, bound together with mortar. In someplaces in the late Lionnois, F. Menestrier observes, that he hasfound huge clusters of flints cemented with lime, reaching 10 or 12feet deep, and making a mass as hard and compact as marble;and which, after resisting tiie injuries of time for 1600 years, isstdl scarcely penetrable by all the force of hammers, mattocks,&c. and yet the flints it consists of are not bigger than eggs. Themost noble of the Roman roads was the Via Appia , which was car-ried to such a vast length; that Procopius reckons it five days jour-ney to the end of it, and Leipsius computes it at 350 miles : it is 12

If feet broad, and made of square free-stone generally a foot and aI half on eaclt side ; and though this has lasted tor above 1800 years,,yet in many places it is.for several miles together as entire as whenit was first made. The ancient roads are distinguished into military,roads, subterraneous roads, See. The military roads were grandroads, formed by the Romans for marching their armies into theprovinces of the empire ; the principal of these Roman roads inEngland are Watling-street, Ikonild-street, Foss-way, and Ermin-age-street. Double roads among the Romans, were roads, forcarriages, with two pavements, the one for those going one way,and the other for those returning the other these were separatedfrom each other by a causeway raised in the middle, paved withbricks, for tile convenience of foot-passengers ; with borders andmounting stones from space to space, and military columns tomark the distance. Subterraneous roads are those dug through arock, and left vaulted ; as that of Puzztmli near Naples, whichis near half a league long, and is 15 feet broad and as many

high-

Roads, Laws respecting. 'I’he first law enacted respecting-highways and roads in England was in 1285; when the lords ofthe soil were enjoined to enlarge those ways where bushes, woods,or ditches were, in order to prevent robberies. The next law was.marie by Edward III . in 1346 ; when a commission was granted,by the king to lay a toll on all sorts of carriages passing from thehospital of St. Giles in the fields to the bar of the Old Temple,and also through another highway called Portpool (now Gray’sInn Lane) joined to the before named highway ;. which roads were,become almost impassable. Little further relating to this subjectoccurs, till the reign of Henry VIII . when the parishes were en-trusted with the care of the roads, and surveyors were annuallyelected to take care of tliepi. But the increase of luxury' and com-merce introduced such a number of heavy carriages for the con-veyance of goods, and lighter ones for the convenience and easeof travelling, that parish-aid was found insufficient to keep the bestfrequented roads in repair. This introduced toll-gates or turn-pikes ; that something might be paid towards their support byevery individual who enjoyed'the benefit of these improvements,,by passing over the roads.

Road, in navigation, is a place of anchorage at some- distancefrom shore, where vessels usually moor, to wait fora wind or tideproper to carry them into harbour, or to set sail. When the bot-tom is firm, clear of rocks, and sheltered from the wind, it is called ■a good road ; and when there is but little land on any side, it istermed an open road. The roads in his majesty’s dominions arefree to ajl--merchant-vessels, belonging to his subjects and allies.Captains and masters of ships who are forced by storms, &c. tocut their cables, and leave their anchors in the roads, are obligedto fix marks or buoys, on pain of forfeiting their anchors, &c.Masters of ships coming to moor in a road, must cast anchor atsuch a distance, as that the cables, &c. do not mix, on pain ofanswering the damages; and when there are several vessels in thesame road, the outermost to the sea-ward is obliged to keep a lightin his lanthorn in the night-time tb apprize vessels coming in fromsea.

ROANNE, a populous and commercial town of France , in thedepartment of the Rhone and Loire, anti late province of Lyon-nois, 50 miles N. E. of Clermont, and 210 S. E. of Paris .

ROANOAK, or ROANOKE, an island of North America ,near the coast of N. Carolina. Here the English first attemptedto settle in 1585, but were obliged to Rave it for want of provi-sions. Lon. 75. 0. E. Lat. 35. 40. N.

Roanoke, a river of N. America, which rises in Virginia , runsthrough N. Carolina , and at length falls into the sea, where itforms a long bay called Albemarle bound.

Roanoke Inlet, an inlet on the coast of Ni Carolina, leading,into Albemarle Sound. Lon. 75. 14. W. Lat. 35. 56. N.

Roanoke Island, an island on the S. side ot Albemarle Sound,about 7 miles W. of the Inlet.

ROASTING, in metallurgy, the separation of volatile bodiesfrom those which are more fixed, by the combined action of air 'and fire; and is generally the first process in the separation ofmetals from their ores : it diHers from sublimation only in this,that in tjiis operation the volatile parts are dissipated, when re-solved into vapours : whereas in tliat they arc preserved.

ROBBERY, the rapine of the civilians, is the felonious and4 forcible