BUBBLE 137 RUBICON medical apparatus, rubber is increasingly used in articles of commerce both in the hard rubber and soft rubber state. One of its most valuable uses is as an adjunct to the electrical industry in which it is found of great service as an insulating material. RUBBLE, a common kind of masonry, in which the stones are irregular in size and shape. Walls faced with ashlar are generally packed with rubble at the back. Rubble is of various kinds, according to the amount of dressing given to the stones. Common rubble is built with stones left almost as they come from the quarry. Hammer-dressed rubble is so called when the stones are squared with the mason's hammer; coarsed rubble, when the stones are squared and equal in height, etc. RUBEFACIENTS, external agents em- ployed in medicine for the purpose of stimulating, and consequently reddening, the part to which they are applied. All agents which, after a certain period, act as blisters may be made to act as rube- facients, if their time of action is short- ened. The mildest rubefacients are hot poultices, cloths soaked in very hot water, moderately stimulating liniments — as, for example, soap-liniment, with various pro- portions of liniment of ammonia, or chlo- roform, etc. Spanish fly, in the form of Emplastrum Calefaciens, or warm plaster, in which the active ingredient is blunted by the free admixture of soap plaster, resin plaster, etc., is a good form of this class of agents. Capsicum or cayenne pepper, in the form of a poultice, is an excellent rubefacient; it is much used in the West Indies. Mustard, in the form of Cataplasma Sinapis, or mustard poul- tice, and oil of turpentine are perhaps the best of the ordinary rubefacients. The best method of employing turpentine is to sprinkle it freely on three or four folds of clean flannel wrung out of boiling water. The sprinkled surface of this pad is placed on the skin, and a warm dry towel is laid over the flannel. RUBELLITE, in mineralogy, a red variety of Tourmaline (q. v.), occurring in crystals mostly transparent and con- taining lithia. RUBENS, PETER PAUL, a distin- guished Flemish painter; born in Siegen, Westphalia, June 29, 1577. When he was 10 years old, his mother, then a widow, returned to her native place, Antwerp. He received an excellent education; and after studying in his own country, espe- cially under Otto Van Veen, he went to Italy, where he improved himself by copy- ing the works of the best masters, but chiefly Titian. While in Italy he was employed by the Duke of Mantua, not only as an artist, but on an embassy to Madrid. He returned to Antwerp in 1808, and was soon after made court painter to the Archduke Albert, Spanish gov- ernor of the Low Countries. In 1620 he was employed by the Princess Mary de Medici to adorn the gallery of the Luxem- bourg with a series of paintings illustra- tive of the principal scenes of her life. PETER PAUL RUBENS While thus engaged he became known to the Duke of Buckingham, who purchased his museum. He was afterward employed by the Infanta Isabella and the King of Spain in some important negotiations which he executed with such credit as to be appointed secretary of the privy coun- cil. He acquired immense wealth, and was twice married, the second time, in 1631, to a lovely girl of 16. Rubens, be- yond all comparison, was the most rapid in execution of all the great masters, and was incontestably the greatest perfector of the mechanical part of his art that ever existed. His works are very numer- ous, and very diversified in subject. There are nearly 100 in the Picture Gallery at Munich. "The Descent from the Cross," at Antwerp, is perhaps his mas- terpiece. He died in Antwerp, May 30, 1640. RUBIACE.SJ, an order of plants founded by Jussieu in 1759 ; monopetalous plants, with opposite leaves, interpetiolar stipules; stamens inserted in the tube of the corolla, and alternating with its lobes; ovary inferior, compound. RUBICON, a river in north Italy (now the Fiumicino, a tributary of the Adriatic), famous in Roman history, Csesar 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
