RIESENGEBIRGE RIFLE 327 keeper, he was arrested and led to the foot of the capitol stairs, where, while in the act of addressing the people, he was run through the body by Cecco del Vecchio, an artisan, and was forthwith despatched by a hundred weapons, his head cut off, and his body treat- ed with shameful indignities. An important series of letters, addressed by Rienzi to the emperor and the archbishop of Prague after his first fall, and vividly illustrating his charac- ter, was discovered by Pelzel, the historian of Bohemia, in the last century, and was in 1841 published in German by Dr. Papencordt, under the title of Cola di Riemi und seine Zeit (Ham- burg and Gotha). Some of them are given in Hobhouse's " Illustrations to Childe Harold." The story of Rienzi forms the groundwork of one of Bulwer's best known novels. RIESENGEBIRGE (Giant mountains), a range of mountains partly separating Prussian Silesia from Bohemia, and with the Lusatian range forming a continuation E. of the river Elbe of the Erzgebirge range W. of that river. The Riesengebirge belong to the N. W. division of the Sudetic mountain system, and pursue a S. E. course from the sources of the Bober to those of the southern Neisse until they are merged in the Glatzergebirge, of the Sudetic mountains proper. The range extends about To m., with a breadth of 30 m., and is of the same general geological structure with the Erzgebirge, the rocks being chiefly metamor- phic slates and granites, and productive in a similar variety of valuable ores. Those of iron are especially abundant, and some of the ear- liest establishments for producing that metal were in this region. The highest summits are the Schneekoppe, which rises to an alti- tude of upward of 5,000 ft., and the Hohes Rad, and the Grosse and Kleine Sturmhaube, all of which are about 4,500 ft. high. RIETSCHEL, Ernst Friedrieh August, a German sculptor, born in Pulsnitz, Saxony, Dec. 15, 1804, died in Dresden, Feb. 21, 1861. He studied under Rauch and in Italy, settled in Dresden, and was appointed professor in the academy of fine arts. Among his works are a colossal group of " Mary weeping over the Body of Christ;" statues of Lessing," Goethe, Schiller, and "Weber; "Love taming a Pan- ther;" "Love borne by a Panther;" the "Four Hours of the Day;" and busts of Lu- ther and Augustus II. of Poland and Saxony for the Walhalla. RIFLE (Dan., Rifle or Eiffel, a chamfer; Ger. reifeln or riffeln, to chamfer or groove), a term applied solely until within the past 25 years to small arms, the surfaces of whose bores are spirally grooved to increase the accuracy of their fire. Rifles are supposed to have been invented in the latter part of the 15th centu- ry, by Gaspard Zollner of Vienna. They are known to have been used in target firing at Leipsic in 1498. The first rifles were made with their grooves parallel to the axis of the bore, and although no increased accuracy was given to the fire by such grooving in theory, yet in practice the firing was better, because the grooves allowed the windage to be dimin- ished, and formed receptacles for the residuum of the firing, which in smooth-bores lodged on the surface of the bore, causing wild shoot- ing after a few discharges. The effect of spi- ral grooving was probably discovered acciden- tally, and the date of the discovery cannot be determined. In 1563 a law of the Swiss can- ton of Bern prohibited the use of arms with spiral rifling in target shooting, on account of the discord which such arms produced among the competitors. Some accounts name as the inventor Augustin Kutter of Nuremberg, who died in 1630. The advantages of rifling were first discussed scientifically in " New Princi- ples of Gunnery" (1742), by Benjamin Robins, an English mathematician, who died in 1Y51. He mentions breech-loading arms as in use in Europe at that time. That length in the di- rection of the bore in which the spiral rifling would make one turn is called the "twist," the parts cut out of the surface of the bore are the "grooves," and the spaces between the grooves are the "lands." The grooves are as nearly parallel to each other as they can be made, and generally have a constant inclina- tion to the axis of the bore. In this case the twist is said to be uniform. There is another kind of twist, in which the groove starts from the breech parallel to the axis of the bore, and gradually inclines from this line until it attains the required angle, where it remains constant. This is called a "gaining twist." It is now only used in small pistols, and has little if any advantage over the uniform twist. The centres of gravity and of figure of a lead or iron ball do not generally coincide, and the diameter of the ball of a smooth-bore is neces- sarily smaller than that of the bore of the piece. It follows from the first fact that the line of direction of the force exerted upon the ball by the powder does not generally pass through its centre of gravity, causing a ten- dency to revolve about an axis passing through that centre, which axis will, not coincide with the axis of the bore or the tangent to the tra- jectory, thus forming one source of deviation of the projectile from the theoretic trajectory. It follows from the second fact that the ball as it advances through the piece will bounce against the surface of the bore, causing a mo- tion of rotation about some unknown axis ; this is another source of deviation. If these sources of deviation be removed, the projectile will move in the theoretic trajectory, and will strike the point aimed at, if the other condi- tions to attain this end have been complied with. If a barrel be rifled, and the ball so made that projections on its surface precisely fit the grooves of the rifling, the ball in pass- ing through the barrel must receive a motion of rotation about the axis of the bore; and as the axis of rotation will then nearly or quite coincide with the tangent to the trajectory du-
