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divine; whereof they published themselves the restorers. Theypretended to be masters of many important secrets, and, amongothers, of the philosopher’s stone ; all which they affirmed to havereceived by tradition from the ancient Egyptians, Chaldeans, theMagi, and Gymnosophists. They have been distinguished by se-veral names, from the several branches of their doctrine, lie-cause they pretend to protract the period of human life, by meansof certain nostrums, and even to restore youth, they were calledImmortales; as they pretended to know all things they havebeen called Illuminati; and because they have made no appear-ance for several years, they have been called the invisible brothers.Their society is often signed by letters F. R. C. which someamong them interpret fratres roris cocli; it being pretended, thatthe matter of the. philosophers’ stone is dew concocted, exhaled,&c. Some make the present flourishing society of free-masons abranch of Kosicrucians; or rather the Rosicrucians themselves,under a new name, frame, or relation, viz. as retainers to building.

ROS1ENNE, a town of Samogitia , on the Dubisse; 70 miles !S. of Mittau, and 188 N. E. of Warsaw. Lon. 23. 43. E. Eat.

53. 30. N.

HOSIERS AUX SALINES, a town of France , In the depart-ment of the Meuniie, and late province of Lorraine, famous for itssalt-works. It is 9 miles S. E. of Nanci, and 170 E. of 1’aris.

Hosiers, Cape, a cape upon the S. boundary of the river St.Lawrence . Lon. fid. 40. W. Lat. 48. 5ti. N.

ROSIN. See Resin.

ROSKILD, formerly the royal residence and metropolis ofDenmark , stands at a small distance from the bay of Isefiord, notfar from Copenhagen .

ROSMARINUS, Rosemary; in botany, a genus of the mo-nogynia order, ai*l diandria class of plants; natural order, Verti-cil lata'. Corolla unequal, with the upper lip two-parted; fila-ments long, curved, simple, with a tooth. There are two spe-cies, viz. U. officinalis, officinal rosemary ; and R. Chilensis, Chilirosemary.

ROSOY, a town of France, in the department of Seine andMarne, and late province of the Isle of France , 15 miles S. ofMeaux .

ROSS, or ROSS-SI1IRE, a county of Scotland , includingTayne ami Cromarty, stretching 80 miles in length, and 78 inbreadth, is bounded on the N. and N. E. by Strathnaver and Su-therland ; on the E. by Cromarty and the Mnrray-Frilh; on theS. by Inverness ; and on tbe \V. by (be Isle of Sky and theWestern Ocean. Tayne includes the greater part of Ross, withthe isles of Sky, Lewi*, and Harris, Cromarty lies on the otherside of the Murray-Frith. The county of Ross has many hugemountains, on which the snow lies great part of the year: these,however, yield good pasture ; but on the E. side, next the Ger-man ocean, it admits of agriculture, and produces good crops ofcorn. The valleys are fertilized by several rivers.

Ross, an ancient and populous town of England, in Hereford-shire, 1 IS miles from London , with a good trade, on the riverWye. Lon. 2. 25. W. Lat. 51. 56. N.

Ross, or Ross Carherry, a sea-port-town of Ireland, in Cork ,M mister, seated on a bav of the Atlantic, 20 miles S. W. of Kin- jsale 1 . Lon. 8. 55. W. Cat. 51. 20. N,

RossJsi.ano, an island of Ireland, in Kiliarney Lake, Mun-ster ; containing about 100 acres of ground.

Res*, New, a borough-town of Ireland, 'in the county of Wex-ford, and province ot Leinster , eight miles N. by E. of Waterford,and 15 S. of Wexford .

ROSSANO, a strong town of Naples, in Calabria Citra. Lon16. 52. E. let. 39. 45.' N.

ROS SUfLIS, Sun-dew; an agreeable spirituous liquor, com-posed of burnt brandy, sugar, cinnamon, anti milk-water ; andsometimes perfumed with a little musk. It has its name frombeing at first prepared wholly of the juice of the plant ros-solis, ord.osera.

ROSTER, a roll or register, kept by the brigade-major. SeeMajor.

ROSTOCK, a town in l r pper Saxony . Lon. 12. 53. E. Lat.

54. 8. N.

ROSTOFF, or ROSTOW, a duchy of Russia , houndedonthe N< by Jaroslow, oil the E. by Sutdal, S. by the duchy ofMoscow , and W. by that of Tuere.

Rostoff, or Rostow, a large town in the above territory.Lon. 40. 15. E. Lat. 57. 5. N.

ROSTRA, in antiquity, a part of the Roman forum, whereinorations, pleadings, funeral-harangues, &c. were delivered.

ROT, a very fatal disease incident to sheep, arising from wetseasons, and too moist pasture. It i very difficult of cure, and isattended with the singular circumstance of a kind of animals beingfound in the blood-vessels.

ROTA, an ecclesiastical couit of Rome , composed of twelveprelates, of whom one must be a German , another a Frenchman,aiul two Spaniards: the other eight were Italians , of whom threemust be Romans, and the other live a Bolognese, a Ferrarese, aMilanese, a Venetian, and a Tuscan. This is one of the mostaugust tribunals in Rome , which takes cognizance of all suits inthe territory of the church, b> appeal; as also of all matters bene-ficiary and patrimonial.

Rota, in geography, a town of Spain, in Andalusia , at the en-trance of the Bav of Cadiz; seven miles N. of Cadiz . Lon. 6.16. W. Lat. 36. 35. N.

Rota Aristoteuca, or Aristotle's Wheel, denotes a cele-brated problem in mechanics concerning the motion or rotation ofa wheel about its axis; so called because first noticed by Aristotle ,'lire difficulty is this: While a circle makes a revolution on itscentre, advancing at the same time in a right line along a plane,it describes, cn that plane, a right line which is equal to iis circum-ference. Now if this circle, which may lie called the deferent,carry with it another smaller circle, concentric with it, like uienave of a coach-wheel; then this little circle, or nave, will de-scribe a line in the time of the revolution, which shall he equal tothat of the large wheel or circumference itself; because its centreadvances in a right line as fast as that of tin; w heel doe*, being inreality the same with it. The solution given by Aristotle , is nomore than a good explication of the difficulty. The great Gali-leo next attempted it, hut failed, as did also Tacquet , with nobetter success. After the fruitless attempts of so many great men,M. Dorlous de Meyran, a French gentleman, had the good for-tune to hit upon a solution, which is to this effect: The wheel ofa coach is only acted on, or drawn in a right line ; its rotation orcircular motion arises purely from the resistance of the groundupon which it is applied. Now this resistance is equal to the forcewhich draws the wheel in (lie right line, inasmuch as it defeats thatdirection ; of consequence the causes of the two motions, the oneright and the other circular, are equal. And hence the wheel de-scribes a right line on the ground equal to its circumference. Asfor the nave of (he wheel, the case is otherwise. It is drawn in aright line by the same force us the wheel; but it only turns roundbecause the wheel doer, so, anil can only turn in the same timewith it. lienee it follows, that its circular velocity is less than thatof the wheel, in (he ratio of the two circumferences; and thereforeits circular motion is less than the rectilinear one. Since then itnecessarily describes a right line equal to that of the wheel, it canonly do it partly by sliding, and partly by revolving, the slidingpart being more or less as the nave itself is smaller or larger.

ROTACE-iE, [from rota, u wheel, j the twentieth order in Lin-iiams’s Fragments of a Natural Method, consisting of plants w ithone flat wheel-shaped petal. See Botany .

ROTA LA, in botany, a genus of the monogynia order, and tri-andria i lass of plants. Cali x three-toothed ; corolla none; cap-sule three-celled, many-sceded. There is but one species, viz. R.vertiei'lai is, a native of Ike East Indies,

ROTATION , is a term which expresses the motion of the dif-ferent parts of a solid body round an axis, and distinct from theprogressive motion which it may have in its revolution round a dis-tant point. The earth has a rotation round its axis, w hich producesthe vicissitudes of day and night; while' its revolution round thesun, combined with the obliquity of the equator, produc es the va-rieties of summer and winter, The mechanism of this kind ofmotion, or the relation which subsists between the intensity of themoving forces, modified as it may be by the manner of applica-tion, and the velocity of rotation, is highly interesting, both to thespeculative philosopher, and to the practical engineer. The pre-cession of the equinoxes, and many other astronomical problemsof great importance and difficulty, receive their solutions from thisquarter: and the actual performance of our most valuable machinescannot be ascertained by (lie mere principles of equilibrium, but

require