Page:EB1911 - Volume 04.djvu/970

 religious influences intruded upon Palestine, the cult of its local numen gave place to the worship of Pan, to whom was dedicated the cave in which the copious spring feeding the Jordan arises. It was long known as Panium or Panias, a name that has survived in the modern Banias. When Herod the Great received the territory from Augustus, 20, he erected here a temple in honour of his patron; but the re-foundation of the town is due to his son, Philip the Tetrarch, who here erected a city which he named Caesarea in honour of Tiberius, adding Philippi to immortalize his own name and to distinguish his city from the similarly-named city founded by his father on the sea-coast. Here Christ gave His charge to Peter (Matt. xvi. 13). Many Greek inscriptions have been found here, some referring to the shrine. Agrippa II. changed the name to Neronias, but this name endured but a short while. Titus here exhibited gladiatorial shows to celebrate the capture of Jerusalem. The Crusaders took the city in 1130, and lost it to the Moslems in 1165. Banias is a poor village inhabited by about 350 Moslems; all round it are gardens of fruit-trees. It is well watered and fertile. There are not many remains of the Roman city above ground. The Crusaders’ castle of Subeibeh, one of the finest in Palestine, occupies the summit of a conical hill above the village.

CAESIUM (symbol Cs, atomic weight 132.9), one of the alkali metals. Its name is derived from the Lat. caesius, sky-blue, from two bright blue lines of its spectrum. It is of historical importance, since it was the first metal to be discovered by the aid of the spectroscope (R. Bunsen, Berlin Acad. Ber., 1860), although caesium salts had undoubtedly been examined before, but had been mistaken for potassium salts (see C. F. Plattner, Pog. Ann., 1846, p. 443, on the analysis of pollux and the subsequent work of F. Pisani, Comptes Rendus, 1864, 58, p. 714). Caesium is found in the mineral springs of Frankenhausen, Montecatini, di Val di Nievole, Tuscany, and Wheal Clifford near Redruth, Cornwall (W. A. Miller, Chem. News, 1864, 10, p. 181), and, associated with rubidium, at Dürkheim; it is also found in lepidolite, leucite, petalite, triphylline and in the carnallite from Stassfurt. The separation of caesium from the minerals which contain it is an exceedingly difficult and laborious process. According to R. Bunsen, the best source of rubidium and caesium salts is the residue left after extraction of lithium salts from lepidolite. This residue consists of sodium, potassium and lithium chlorides, with small quantities of caesium and rubidium chlorides. The caesium and rubidium are separated from this by repeated fractional crystallization of their double platinum chlorides, which are much less soluble in water than those of the other alkali metals (R. Bunsen, Ann., 1862, 122, p. 347; 1863, 125, p. 367). The platino-chlorides are reduced by hydrogen, and the caesium and rubidium chlorides extracted by water. See also A. Schrötter (Jour. prak. Chem., 1864, 93, p. 2075) and W. Heintz (Journ. prak. Chem., 1862, 87, p. 310). W. Feit and K. Kubierschky (Chem. Zeit., 1892, 16, p. 335) separate rubidium and caesium from the other alkali metals by converting them into double chlorides with stannic chloride; whilst J. Redtenbacher (Jour. prak. Chem., 1865, 94, p. 442) separates them from potassium by conversion into alums, which C. Setterberg (Ann., 1882, 211, p. 100) has shown are very slightly soluble in a solution of potash alum. In order to separate caesium from rubidium, use is made of the different solubilities of their various salts. The bitartrates RbHC4H406 and CsHC4H406 have been employed, as have also the alums (see above). The double chloride of caesium and antimony 3CsCl·2SbCl3 (R. Godeffroy, Ber., 1874, 7, p. 375; Ann., 1876, 181, p. 176) has been used, the corresponding compound not being formed by rubidium. The metal has been obtained by electrolysis of a mixture of caesium and barium cyanides (C. Setterberg, Ann., 1882, 211, p. 100) and by heating the hydroxide with magnesium or aluminium (N. Beketoff, Chem. Centralblatt, 1889, 2, p. 245). L. Hackspill (Comptes Rendus, 1905, 141, p. 101) finds that metallic caesium can be obtained more readily by heating the chloride with metallic calcium. A special V-shaped tube is used in the operation, and the reaction commences between 400° C. and 500° C. It is a silvery white metal which burns on heating in air. It melts at 26° to 27° C. and has a specific gravity of 1.88 (15°C.).

The atomic weight of caesium has been determined by the analysis of its chloride and bromide. Richards and Archibald (Zeit. anorg. Chem., 1903, 34, p. 353) obtained 132.879 (O=16).

Caesium hydroxide, Cs(OH)2, obtained by the decomposition of the sulphate with baryta water, is a greyish-white deliquescent solid, which melts at a red heat and absorbs carbon dioxide rapidly. It readily dissolves in water, with evolution of much heat. Caesium chloride, CsCl, is obtained by the direct action of chlorine on caesium, or by solution of the hydroxide in hydrochloric acid. It forms small cubes which melt at a red heat and volatilize readily. It deliquesces in moist air. Many double chlorides are known, and may be prepared by mixing solutions of the two components in the requisite proportions. The bromide, CsBr, and iodide, CsI, resemble the corresponding potassium salts. Many trihaloid salts of caesium are also known, such as CsBr3, CsClBr2, CsI3, CsBrI2, CsBr2I, &c. (H. L. Wells and S. L. Penfield, Zeit. für anorg. Chem., 1892, i, p. 85). Caesium sulphate, Cs2SO4, may be prepared by dissolving the hydroxide or carbonate in sulphuric acid. It crystallizes in short hard prisms, which are readily soluble in water but insoluble in alcohol. It combines with many metallic sulphates (silver, zinc, cobalt, nickel, &c.) to form double sulphates of the type Cs2SO4·RSO4·6H2O. It also forms a caesium-alum Cs2SO4·Al2(SO4)3·24H2O. Caesium nitrate, CsNO3, is obtained by dissolving the carbonate in nitric acid, and crystallizes in glittering prisms, which melt readily, and on heating evolve oxygen and leave a residue of caesium nitrite. The carbonate, Cs2CO3, silicofluoride, Cs2SiF6, borate, Cs2O·3B2O3, and the sulphides Cs2S·4H2O, Cs2S2·H2O, Cs2S3·H2O, Cs2S4 and Cs2S6·H2O, are also known.

Caesium compounds can be readily recognized by the two bright blue lines (of wave length 4555 and 4593) in their flame spectrum, but these are not present in the spark spectrum. The other lines include three in the green, two in the yellow, and two in the orange.

CAESPITOSE (Lat. caespes, a sod), a botanical term for “growing in tufts,” like many grasses.

CAESTUS, or (from Lat. caedo, strike), a gauntlet or boxing-glove used by the ancient pugilists. Of this there were several varieties, the simplest and least dangerous being the meilichae ( ), which consisted of strips of raw hide tied under the palm, leaving the fingers bare. With these the athletes in the palaestrae were wont to practise, reserving for serious contests the more formidable kinds, such as the sphaerae ( ), which were sewn with small metal balls covered with leather, and the terrible murmekes ( ), sometimes called “limb-breakers” ( ), which were studded with heavy nails. The straps ( ) were of different lengths, many reaching to the elbow, in order to protect the forearm when guarding heavy blows (see J. H. Krause, Gymnastik und Agonistik der Hellenen, 1841). The caestus is to be distinguished from cestus (=embroidered, from  ), an adjective used as a noun in the sense of “girdle,” especially the girdle of Aphrodite, which was supposed to have the power of exciting love.

CAESURA (Lat. for “cutting,” Gr.  ), in prosody, a rest or pause, usually occurring about the middle of a verse, which is thereby separated into two parts (, members). In Greek and Latin hexameters the best and most common caesura is the penthemimeral (i.e. after the 5th half-foot):

 |, | , |  |  |  | Arma vi | rumque ca | no, Tro | jae qui | primus ab | oris.

Another caesura very common in Homer, but rare in Latin verse, is after the 2nd syllable of the 3rd dactyl:

 |  |   |   |  |.

On the other hand, the hephthemimeral caesura (i.e. after the 7th half-foot) is common in Latin, but rare in Greek:

Formo | sam reso | nare do | ces Ama | ryllida | silvas.

The “bucolic” caesura, peculiar to Greek (so called because it is chiefly found in writers like Theocritus) occurs after the 4th dactyl:

 |, | ,  | , |   |

In the pentameter verse of the elegiac distich the caesura is always penthemimeral. In the iambic trimeter (consisting of three dipodia or pairs of feet), both in Greek and Latin, the most usual caesura is the penthemimeral; next, the hephthemimeral:

 | |   |  |  | Supplex | et o | ro reg | na per | Proser | pinae.