More than one of these 7 encyclopedias carries each of the following subjects — but every one of them treats it in a sentence or two and then moves on. They are gathered here so the different accounts can sit side by side.
Rock Salt
Collier's New Encyclopedia: common salt, or chloride of sodium, occurring as a mineral and in a solid form. It is always mixed with various impurities. It is found massive or crystallized, stallized, its crystals generally cubes, its masses very often either granular or fibrous. It is white, gray, or, owing to the presence of impurities, more rarely red, violet, blue, or striped. For its chemical and other qualities, see SALT. It is a very extensively-diffused mineral, and in some places forms great rock and even mountain masses. A hill of rocksalt near Montserrat, in Spain, is 500 feet high. The island of Ormus, in the Persian Gulf, is formed of rock salt. The Indus, in the upper part of its course, forces its way through hills of rock salt. ROCK SCORPION (Buthus or Scorpio afer), a species of scorpion found in Africa, averaging about six inches in length. The bite of this animal, though not absolutely fatal, is yet considered to be dangerous.
Aiton's Encyclopedia: . See Salt
Covered by Collier's New Encyclopedia and Aiton's Encyclopedia
Roman Cement
Collier's New Encyclopedia: a dark-colored hydraulic cement, which hardens very quickly and is very durable. The true Roman cement is a compound of pozzuolana and lime ground to an impalpable powder and mixed with water when used. Other cements bearing the same name are made of different ingredients.
The Encyclopedia of Founding: A beautiful cement, improperly called Roman, is made as follows: Calcine 3 parts of ordinary clay, and mix it with 2 parts lime; grind it to powder, and calcine again.
Covered by Collier's New Encyclopedia and The Encyclopedia of Founding
Rook
Collier's New Encyclopedia: a European species of crow (Corvus frugilegus, Linn.), resembling in size and color the carrion crow, but differing in having the base of the bill whitish and scurfy, and bare of feathers. The rook is gregarious at all seasons, resorting constantly to the same trees every spring to breed. After their young have taken wing, they all forsake their nest trees, returning to them again in October to roost; but as winter comes on, they generally select more sheltered places at night nearby, to which they fly off together.
Aiton's Encyclopedia: . See Crow
Covered by Collier's New Encyclopedia and Aiton's Encyclopedia
Rosemary
Collier's New Encyclopedia: the Rosmarinus officinalis, a native of the S. of Europe and Asia Minor, and cultivated in India, etc.; a very fragrant labiate plant with a white or pale-blue corolla. The leaves are sessile and gray with edges rolled round below. It is sometimes made into garlands. It is slightly stimulant, and tends to relieve headache and mental weariness. It is an ingredient in Hungary-water. It 1 is also used as a conserve, and a liquor is made from it.
Aiton's Encyclopedia: a plant of the mint family, native to the countries of the Mediterranean. It has a fragrant smell and a bitter, pungent taste. An oil obtained from its leaves by distillation is much used as a perfume in the manufacture of pomatums for the hair. Rosemary is a possible corruption of an original name signifying dew of the sea. There's rosemary, that's for remembrance;. . and there is pansies, that's for thoughts.--Shakespeare, Hamlet.
Covered by Collier's New Encyclopedia and Aiton's Encyclopedia
Rouge
Collier's New Encyclopedia: in ordinary language, a cosmetic prepared from the dried flowers of Carthamus tinctorius, and used to impart artificial bloom to the cheeks or lips. Jeweler's rouge: an impalpable preparation of oxide of iron, obtained by gently heating the yellow oxalate of iron till it decomposes, carbonic acid escaping, and only a red powder being left. It is used for polishing silver, and for this purpose should be of the finest quality. Many cheaper varieties are sold under this name. ROUGE ET NOIR (French, "red and black"), TRENTE-UN ("31"), or TRENTE ET QUARANTE ("30 and 40"), a modern game of chance, played by the aid of packs of cards on a table covered with green cloth.
The Encyclopedia of Founding: The light-red powder used for polishing speculums, and extensively employed by jewellers for polishing glass and metal work. The protosulphate of iron is calcined until nothing remains but the anhydrous sesquioxide, which is afterwards submitted to fine levigagation. See SPECULUM; LEVIGATION.
Covered by Collier's New Encyclopedia and The Encyclopedia of Founding
Rubicon
1000 Classical Characters: A small river in Italy. By crossing it, and thus transgressing the boundaries of his province, Caesar declared war against the senate and Pompey. "Passing the Rubicon" has become a proverbial expression, indicating an irrevocable step taken in any weighty matter. Rudiae (Rotigliano or Ruge). A town of the Peucetii in Apulia. Rudiae is celebrated as the birthplace of Ennius . Rullus, P. Servilius. A tribune of the plebs в. c. 63, who proposed an agrarian law, which Cicero attacked in three orations, which have come down to us.
Aiton's Encyclopedia: ru'bi-kon, in classical geography, a little stream in Italy, dividing the province of Gaul from Rome proper. When the Senate at Pompey's instigation gave orders to send home part of his army, Caesar, it is said, rode up and down the banks of the Rubicon debating with himself all night whether to comply or to march on Rome. At daybreak he gave marching orders; hence the proverbial expression, "crossing the Rubicon," denotes taking a decisive step which cannot be retraced. See Caesar ; Pompey
Collier's New Encyclopedia: a river in north Italy (now the Fiumicino, a tributary of the Adriatic), famous in Roman history, Cæsar having by crossing this stream (49 b. c.), at that time regarded as the N. boundary of Italy, finally committed himself to the civil war. Hence the phrase "to pass the Rubicon" is to take the decisive step by which one commits one's self to a hazardous enterprise.
Covered by 1000 Classical Characters and Aiton's Encyclopedia and Collier's New Encyclopedia
Rubidium
Collier's New Encyclopedia: a metal much resembling cæsium, with which it was discovered in 1860, by Bunsen and Kirchoff, during the analysis of a spring of water which contained these metals in minute quantities. Rubidium has since been found in small quantities in other mineral waters, in lepidolite, and in the ashes of many plants. This metal is closely related, in properties, to potassium, but is more easily fusible and convertible into vapor, and actually surpasses that metal in its attraction for oxygen, rubidium taking fire spontaneously in air. It burns on water with exactly the same flame as potassium. Its oxide, rubidia (RbO), is a powerful alkali, like potash, and its salts are isomorphous with those of potash.
Aiton's Encyclopedia: a metallic element of the sodium group. It was detected in 1860 by Bunsen and Kirchoff by means of spectrum analysis applied to a residuum of mineral water. It gives two red lines in the blue part of the flame. It has a specific gravity of 1.52. At ordinary temperatures it is as soft as wax. In appearance and qualities, it resembles potassium, burning like that element explosively on water and slowly in air. See Potassium
Covered by Collier's New Encyclopedia and Aiton's Encyclopedia