IK RUSTIC WORK. 



UM ohinmk brad and (hallow, and the course* to deep that there ro 

 only a few horizontal streak* along the face of a wall. 



Nix 4 U an iiuUnce of chamfered joint* and venniculatwl rustics, 

 bordered, that ia, having a plain rarfaoe around their facet. 



3 ahowa an example of Florentine rusticating with moulded 

 ^....L-I., the effect of which U particularly rich. One of the rustic* 

 a f*autd in the out, in order to give an example of that mode in 

 . . 



So. . 



RUTIC GROUP. 



220 



No. 4. 



No. i. 



No. 4 u another mode peculiar to the Florentine style, in which the 

 ruitics are facetted, or cut so u to form four triangular surfaces. It 

 U not used throughout, but only in the lower course, forming a sort of 



dado to the building. This example ia from the same building as the 

 preceding. 



No. 6 shows one-half of a rusticated arch having Mowed voussoirs 

 running into the horizontal courses. 



No. 6 represents half of another arch with vou&soirs whose txlradot 

 form an eccentric curve from that of the arch itself, or else a pointed 

 arch, while the intradm form a semicircular one. 



No. fl. 



RUTAMIDE. [Rune GBOLT.] 



KUTATES. [Roxic GROW.] 



HUTH, BOOK OF, an acknowledged canonical book of the Old 

 Testament, though Bertholdt and some other German writers have 

 considered it a fiction or parable. The history of Ruth seems to have 

 been inserted in the sacred canon as a necessary link in establishing 

 the pure genealogy of David, and consequently of the Messiah ; and 

 perhaps also to furnish a record of the fact that one of the Messiah's 

 ancestors was a Gentile, thus intimating the truth that the (Jentiks 

 were to have a part in the highest privileges of the Jews. In the 

 ancient Jewish canon this book forms a part of the Book of Judges, 

 because the events recorded in it happened during the rule of the 

 Judges. Its exact date is however uncertain, but most probably the 

 famine mentioned in verse 1 ia that which happened in the time of 

 Gideon, about B.C. 1241. It is generally supposed to have been written 

 by the prophet Samuel. The style is marked by a touching simplii -ity, 

 and some parts of it are very pathetic, (The lutrotluctiunt of Jahu, 

 Eichhorn, De Wette, and Home ; Umbreit, Uebcr Gciat und Zin 

 Bucka KM, 1834.) 



UUTHENIC ACID. [RUTHENIUM.] 



RUTHENIUM (Ru). This metal was shown to exist in platinum 

 ores by Clauss in 1845. According to Deville and Debray, who have 

 specially studied the metals associated with platinum, ruthenium may 

 be prepared from the native osmide by mixing it, in fine powder, with 

 three parts of binoxide of barium and one of nitrate of baryta ; heating 

 the whole to redness in a crucible for an hour ; treating the product 

 with hydrochloric, nitric, and sulphuric acids consecutively ; precipi- 

 tating with chloride of ammonium ; igniting the precipitate ; and 

 finally fusing the residue with nitrate and hydrate of potash. From 

 the rutheniate of potash thus formed, the teroxide of ruthenium, or 

 ruthenic add (Ru0 3 ), may be precipitated by carbonic or nitric acids, 

 and then reduced to the metallic state by heating in a current of 

 hydrogen. 



Ruthenium is only fusible with extreme difficulty. It has a blackish- 

 lirowu surface, and is hard and brittle like indium. Its specific gravity 

 ia 11 to 11'4, and its equivalent 5'2'11. 



Ruthenium and o.ct/gm unite in four different proportions. Pi- 

 (RuO) ; tetquioxlde (Ru,0 s ), the most stable of these oxides, formed 

 on igniting the metal in a current of air ; binoxide (Ru0 2 ), obtained by 

 roasting and igniting the bisulphide ; and ruihenic acid (Ru0 5 ), pre- 

 pared as already described. 



Ruthenium and tidjihur. The sulphides of this metal are probably 

 as numerous as the oxides, but they are very difficult of preparation. 



Kuthenium and chlorine form three compounds. The protochloride 

 (RuCl) results from the ignition of the metal in chlorine gas ; it ia 

 insoluble in water or acids. The sm/uichloride (Ru 2 Cl,) is formed on 

 dissolving the sesquioxide in hydrochloric acid; and the bic/iluridc 

 (BuCL), which exists as a rose-coloured double salt with chloride of 

 potassium. 



T/ie taltt of ruthenium are chiefly those of the sesquioxkle. They 

 have a yellow colour, and alkalies re-precipitate from their solutions 

 the msquioxide as a black powder. A tnlphate, containing RuO.,2SO s , 

 has been obtained. 



:UT1C ACID. [Rune GKOOP.] 



RUTIC GROUP. A cluster of chemical substances containing the 

 electro-negative radical rutyl (C^H^O,). 



