Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/915

 ROS

RIG, or Rigling, the fame with Ridgllng. See the article Ridgling, Cycl.

RING-Ouzcl, the Knglifh name of the black Tardus, with a white ring round its neck. See the article Turdus, SlMl.

RIPENING of fruit, in gardening, may be forwarded feveral ways. The method pradtifed in the Levant, for maturating the domeftic fig-tree, has been already mentioned ; alfo the great ufe of hot beds, for'bringing to maturity many exotic plants, which could not be otherwife effefled in cold cli- mates. See the articles Capri? ication, Suppl. and Hot- beds, Cycl. and Sufpl.

Several other methods of flattening the fructifications of trees, and other vegetables, have likewife been taken notice of under the article Forcing. See the article Forcing, Suppl.

ROBIN (Suppl.) — Ragged-Robin, a name fometimes ufed for the Lychnis. See the article Lychnis, Suppl.

JVake-Romn, the Englifh name of a genus of plants, called by botanifts Arum. See the article Arum, Suppl.

RQCK.-rofe, a name fometimes given to the Cifius of botanifts. See the article Cistus, Suppl.

ROCKET, in botany, the Englifh name of a genus of plants, called by botanifts Eruca. See the article Eruca, Suppl.

Cora-RocKET, or fquare-podded Rocket, a diftinct genus of plants, called by botanifts Erucago. See the article Eru- cago, Suppl.

Garden-RocKZT, a name by which the He/peris of botanifts is fometimes called. Seethe article Hesperis, Suppl.

U'dter-RacKET, or Winter-RocKET, the name of a fpecies of Sifymbriuin. See the article Sisymbrium, Suppl.

ROD (Suppl.) — Shcpierd's-RoD, Dipfacus, in botany, the Englifh name of a diftinft genus of plants. See the articb Dipsacus, Suppl.

ROE-fe/rf, the Englifh name of the Cervus with ramofe, cy- lindric, and ereft horns. It is the fmalleft of the deer-kind,

I and has been called Capreolus and Caprea, tho' without the leaft refemblance of the goat-kind. See the article Capre- olus, Suppl.

ROLLER (Suppl.) is alfo the name by which fome call the Am- pslis, or Garrulus Bohanicus. See thearticleAMPELls, Suppl.

ROOT (Suppl.) — The roots of plants may be reverfed and turned into branches ; and vice verfa, the branches into roots. This is called Planting revirfe. See the articlesPlANT and Planting reverfe^ Append.

Seminal-RooT. See the article SEMINAL, Suppl.

ROPE (Cycl. and Suppl.) — Though it be difficult to give a certain account of the forces required to bend ropes of dif- ferent diameters, in making them go round bodies of differ- ent bigneffes, yet to make no allowance for the lofs of mo- tion fuftained thereby, would be as prejudicial to the prac- tice of mechanics, as it would be to overlook the friction of the parts of engines. The difficulty of afcertaining this force arifes from the different materials of which they are made, their different fiiffnefs, according as they are more or lefs twifted j and fometimes from the temperature of the air, as to moifture and drinefs.

Dr. Defaguliers has computed the forces required to bend Mopes of different diameters, ftretched by different weights, round rollers of different bigneffes : The refult of his expe- riments is expreffed in the following table.

Diameters of the Ropes of three ftrands, expreffed in

tenth parts of an inch

> 5

Weights

liefiftance a-

Retiftancea-

Reliftancea-

ftretching

bout a roller

jout a roller

bout a roller

theru^r,ex-

jf half an

of one inch

1 i inches

preffed in

nch diame-

diameter in

diameter in

lb. avoirdu-

ter, in oz. a-


 * z. avoirdu-

oz. avoirdu-

pois.

voirdupois

pois

pois.

bo lb.

225 oz.

112 ,r oz.

75 «z.

60

90

45

3°

60

45

22 i

15

40

150

75

5°

40

60

30

20

40

30.

'5

10

20

75

37 i

25

20

3°

'5

10

20

■5

7 i

1 *

On the whole, it has been foun'd by experiments, that the difficulty of bending a rope round a roller decreafes directly as the diameter or' the roller increafes ; or is, inverfcly, as the diameter of the roller. See Defaguliers, Experim. Phil. vol. 1. p. 233, fcq,

ROSE ( Suppl. ) — Bay-RosE, the name of a genus of plants, called by botanifts Nerium, or Nerion, See the article Nerion, Suppl.

Campion-RosE, a name fometimes given to the Lychnis. See thearticleLYCHNis, Suppl.

RUL

China-RosE, the name by which fome call the Ketmia of bo- tanifts. See the article Ketmia, Suppl.

Mountain- Bay Rose, a name by which the Chamccrhododehdros of botanifts is fometimes called. See the article Cham;e-

RHODODENDROS, Suppl.

Gelder-RosE, a name fometimes given to the Opulus, or water- elder. See the article Opulus, Suppl.

Rose of Jericho, a name by which fome call the Hefperis. Seethe article Hesperis, Suppl.

South-Sea R ose, a name fometimes given to the Nerion of bo- tanifts. See the article Nerion, Suppl.

Rock-RosE, the name by which the Cijlus of botanifts is fomo- times called. See the article Cistus, Suppl.

RosE-Root^ a name by Which fome call the Anacampferos y or Orpin. See the article Anacampseros, Suppl.

ROSEMARY (Snppl.)+~ Spanifi-RosEM ary, a name fome- times given to the Tbymelcsa of botanifts. See the article Thymel^eA, Suppl.

/Ver's-RosEMARY, a name fometimes given to the CaJJia of botanifts. See the article Cassia, Suppl.

ROSTRATA, in zoology, a name ufed by feveral zoologifts for the Ramphajhs or Toucan, a genus of birds. See the article Ramphastos, Append.

ROTHER, 3. term ufed by Bla?ickley, in his Naval Expofitor, for Rudder. See the article Rudder, Cycl. and Suppl.

ROUCOU, in botany, a name given to a fpecies of Mitella.

ROVES, in fhip-building, fmall fquare pieces of iron, with a hole punched in the middle through which the nail goes, where it is clenched, and binds together the boards of pinnaces; yawles, &c. Blanckley's Naval Expofitor, p. 137.

ROUGHINGS, a word ufed in many parts of the kingdom fot the grafs which comes after mowing. Ruft. Diet, in voc.

ROUP, in poultry, is a filthy boil or fwclling upon their rumps, known by the ftaring, or turning back of the fea- thers.

The Roup, if not foon remedied, will corrupt the whole body ; to prevent which, the feathers are to be pulled away; ' the fwelling laid open, and the matter preiTed out ; after which the part is to be wafhed with fait and water, or brine. Ruft. Diet, in voc.

ROWLUCKS, among fhip-carpenters, fmall fpaces left in the gunwale, where two thoals are let in atfuch a diftance from each other, as to admit the oar, at the end of the loom to lie on to row the boat. Blanckley's Naval Expofitor, p. 188.

RUDBECKIA, In the Linnsean fyftem of botany, the name of a genus of plants, called by Vaillant QbeUfcoiheca, and in Englifh the Dwarf-fun-fozver.

The characters are thefe : The common cup is compofed of a double order of leaves^ fix in each orders and covered with plane, broad, but fhort fquamse j the compofite flower is radiated ; the proper one tubulofe, infundibuliform, with its mouth divided into five fegments ; the ftamina are five very fliort, capillary filaments ; the antheras cylindric ; the germeri of the piftil is placed under the receptacle ; the ftyle is fili- form, and of the length of the flower ; the fiigma is divided into two parts, which bend backwards j the receptacle is pa ■ leaceous and conic ; the feeds are Angle and oblong. Vid. Linnitei Gen: Plant, p. 415.

The fpecies of Rudbeckia are thefe. I. The Rudbeckia, with the lower leaves divided into three lobes, and the upper ones undivided. 2. The cdmpofite laciniated-leaved Rudbeckia. 3. The oblong, hairy-leaved Rudbeckia. 4. The great, fca- brous Rudbeckia. .5. The broad-leaved, many-flowered Rud- beckia. 6. The tall Rudbeckia, with red ftalks. 7. The fmall * fhort-lcaved Rudbeckia. 8. The great-flowered, hairy Rudbeckia. Vid. Hill, Hift. Plant, p. 584.

Rudbeckia is alfo a name ufed by Houfton for the Cohocarpus of Linnaeus. See the article Conocarpus, Append.

RUE (Suppl.) — Dog's-RxsE, a name fometimes given to the Scrcphutaria, or fig-wort. See the article ScRopHularia; Suppl.

Aleadoiv-RuE, the Englifh name of a genus of plants, called by botanifts ThalicJrum. Seethe article Thalictrum; Siippl.

Wall-RuE,- the Englifh name of a diftinct genus of plants, called by botanifts Ruta muraria. See ihe article Rut a ot«- rar'ra, Suppl.

RULE (Cycl.) — Rule of five, or, Compound Rule of Three. What is faid in the Cyclopaedia of this ruW% being more eafily performed by two fimple rules of three, is fometimes true, but not always. In fome cafes, not only five, but feven, or nine terms may be given, from whence it is necefTary to determine an eighth, or a tenthj which indeed might be performed by repeated applications of the fimple rule of three, but not fo expeditioufly. Mr. Jones 1 has therefore given a general rule by which all cafes of the rule of Three or of proportion may be folved. The rule is, i°. Set down the terms exprefling the condition of the queftion, in one line. 2°. Under each conditional term fet its correfponding one in another line. 3 . Multiply the producing terms of one line, and the produced term of

I the