ROC 



27 



ROE 



f the realm. A silver coin of Germany, 

 Denmark, Sweden, &c., of different values 

 in different places. In Brunswick and 

 Baden, it is worth 4s. 2d. ; and the rix- 

 dollar of the kingdom of Hungary is worth 

 a farthing- more. In Denmark, it is worth 

 4. 6J<*.; at Hamburgh, 4s. 7i<*. nearly, 

 and the constitutional rix-dollar of 

 Hanover is very nearly of the same'value 

 (4s. 7'9d.). In Hesse Cassel, it is worth 

 4s. ld. nearly ; in Holland, about 4s. ad. 

 (but the 50-stiver piece is worth only 

 4s. 3j<i.) ; at Lubec, 4s. 6|d. ; in Poland, 

 2s. Hid.; in Prussia, currency 2s. lljd, 

 convention 4s. 2jrf. ; in Saxony, the same 

 nearly; in Sweden, 4s. 6i<i. (late coinage) ; 

 at Wurtemberg, 4s. 2jrf. 



ROAD'STEAD. A place where ships may 

 ride at anchor at some distance from the 

 shore. 



ROAN, Fr. rouan. A bay, sorrel, or 

 black, with grey or white spots inter- 

 spersed very closely ; descriptive of the 

 colour of some horses. 



ROAST'ING. In metallurgy, a process by 

 which the volatile parts of ores are sepa- 

 rated by the application of heat. 



KOBIN'I A. An extensive genus of trees 

 and shrubs. Diadelphia Decandria. The 

 Locust-tree, Rose acacia, Pea-tree, Salt- 

 tree, and Goafs-horn, are the best known 

 species. Temperate and warm climates. 



ROCEL'LIC ACID. An acid discovered by 

 Dr. Heeren in the Rocella tinctoria. It is 

 a solid fatty-looking matter. When 

 heated, it melts and congeals again, at 

 251 F., into a crystalline mass. 



ROCHE'-ALCM. An alum brought from the 

 Levant in small pieces of a pale rose colour : 

 called also rock-alum (Fr. roche, a rock). 



ROCHELLE' SALT. Potassio-tartarate of 

 soda. A triple salt consisting of tartaric 

 acid, soda, and potash. It is administered 

 in medicine, in doses from one drachm to 

 an ounce, as a cathartic. 



ROCH'ET (French). 1. A surplice; the 

 white upper garment of an officiating 

 priest. 2. A fish, the roach. 



ROCK, Fr. roc or roche. In geology, a 

 term comprehending all the materials 

 forminst the crust of the globe ; clay, sand, 

 coal, and chalk, as well as limestone, gra- 

 nite, slate, and basalt, and other hard and 

 solid masses, to which the use of the term 

 in common language is generally re- 

 stricted. There are, (1.) Alluvial rocks, 

 formations of recent date ; (2.) Secondary 

 rocks (sometimes named floetz rocks, be- 

 cause they are often disposed horizon- 

 tally) ; these consist partly of chemical, 

 and partly of mechanical deposits, rest- 

 ing upon the (3) Transition rocks. These 

 rest on the primary rocks, and contain 

 the first indications of life, and mark the 

 t'lnrition of the world from an unin- 

 bsHtibin to an inhabited condition ; (4.) 

 *nmary rocke (q. T.). 



ROCK-BI-T'TER. Native alum which 

 occurs in cavities and fissures of argilla- 

 ceous slate in soft masses, of a yellowish- 

 white colour. It is mingled with clay 

 and oxide of iron. 



ROCK-CORK. Mountain-cork. A grey- 

 ish-white variety of asbestos, found in 

 France and Germany. 



ROCK-CRYS'TAL. The most perfect va- 

 riety of quartz. It occurs crystallised in 

 chasms and clefts of the older rock in all 

 countries ; but is found in greatest per- 

 fection in Dauphine, in the Alps, Mada- 

 gascar, &c. The name has been extended 

 to all crystallised and diaphanous va- 

 rieties. 



ROCK-FISH. The gobius niger, Cuv. and 

 Yarr., is so named from its inhabiting 

 rocky situations, but it is more commonly 

 known as the black goby. British coasts. 



ROCKING-STONES. Immense masses of 

 rock, which appear to have been loosened 

 by some convulsion of nature, and, with 

 a slightly rounded base resting on a flat 

 surface of rock below, are easily moved 

 or rocked: called also loggan or laggan- 

 stones. 



ROCK-RCJBY. A name sometimes given 

 to the garnet when it has a shade of blue. 



ROCK-SALT. Mineral salt (native crys- 

 tallised chloride of sodium). In America, 

 the name is sometimes given to salt ob- 

 tained in large crystals. See SALT. 



ROCK-SAM'PHIRE. A plant, the sea-fen- 

 nel (Crithmum maritimwn) , used as a con- 

 diment when pickled with vinegar and 

 spice. 



ROCK-SHELLS. The common name of 

 certain univalves having their shells ter- 

 minated by long straight canals. 



ROCK-WOOD. Lignifprm asbestos. A 

 variety of asbestos which closely resem- 

 bles fossil wood in appearance. 



ROCK-WORK. 1. In architecture, ma- 



nry wrought in imitation of rough 



stone, chiefly used in basements. 2. In 



gardening, a pile of stones, &c.. forming a 

 nidus for the growth of Alpine plants. 



ROD, perch, pole. A long measure of 

 16J feet; also a square measure of 272$ 

 square feet. 



RODEN'TIA. An order of mammalia cha- 

 racterised by two large incisor teeth in 

 each jaw, separated from the molars by 

 an empty space ; they cannot seize living 

 prey nor tear flesh, nor even cut food, but 

 they serve to file, and by continued la- 

 bour to reduce it into separate particles 

 in a word to gnaw it ; hence the term ro- 

 dentia or gnawers, which is applied to 

 animals of this order. The squirrels, 

 marmots, dormice, rats, gerbils, hares, 

 rat-moles, beavers, porcupines, rat-hares, 

 guinea-pigs, mocos, agoutis, and pacas, 

 all belong to this order. 



ROE, Ger. rogen. The spawn of fisbe*. 

 The soft roe or milt denotes the mai* 



2 s 2 



