Page:The American Cyclopædia (1879) Volume XVI.djvu/286

266 VAR The vaporization of liquids under greatly in- creased pressure, as when they are heated in confined spaces, also exhibits remarkable phe- nomena. Alcohol, when heated in a space a little more than twice its volume to 404'6 F., expands to twice its original volume and sud- denly becomes converted into vapor. A glass tube one third filled with water becomes opaque when highly heated, and bursts after a few seconds. The opacity of the tube is due to the chemical action of the water. If the space occupied by the water is one fourth of that of the whole tube, the liquid will be converted into vapor at about 772 F. "When chloride of ethyle is heated in a very thick sealed glass tube, the upper surface becomes indistinct at about 338, and is replaced by an ill defined nebulous zone. As the temperature rises the zone increases in breadth, and becomes more transparent, until finally the tube appears as if empty. Ether becomes completely vaporized in a space three times its volume at about 375. The passage of a liquid into vapor is attended with a remarkable disappearance of heat, which is converted into another form of energy by which the particles are kept asunder. In ordinary language, such heat is said to be- oome latent. (See HEAT.) VAR, a S. E. department of France, in Pro- vence, bordering on Basses- Alpes, Alpes-Mari- times, Bouches-du-RhSne, and the Mediter- ranean ; .area, 2,349 sq. m. ; pop. in 1872, 293,- 757. The Hyeres islands lie off the coast, which is indented by numerous bays, including those of Frejus, Hyeres, and Toulon. The sur- face is generally mountainous and rugged, par- ticularly in the north and northeast, where it is traversed by offshoots of the Alps, and the only extensive tracts of level ground lie along the coast. The principal rivers are the Verdon and Argens, and there are several extensive lagoons along the coast. Coal, iron, and lead are found, but only the first is worked. About one third of the surface is covered with for- ests. The soil is not naturally fertile. The manufactures and productions consist chiefly of wine, fruit, silk, paper, leather, coarse wool- lens, perfumes, and olive oil. The coast fish- eries are valuable, particularly those of tunny and anchovies. The department is divided into the arrondissements of Draguignan, Tou- lon, and Brignoles. Capital, Draguignan. The river Var, from which the department takes its name, flows through the arrondissement of Grasse in the department of Alpes-Maritimes, detached from that of Var in 1861. It risei in the Maritime Alps, was formerly in part the boundary between France and Italy, and falls into the Mediterranean 5 m. S. W. of Nice. VARANGIANS. See NORTHMEN, vol. xii., 498. VARGAS, Luis de, a Spanish painter, born in Seville in 1502, died there in 1568. He com- pleted his studies in Rome, and spent many years in Italy, after which he greatly improved the school of Seville. His death was acceler- ated by the tortures which he endured in his VARICOSE VEINS ascetic frenzy. His portrait of the duchess of Alcala was regarded as equal to the works of Raphael. Only vestiges remain of his large religious fresco and oil paintings, but several of his most celebrated works are still extant, the best known being his painting represent- ing the human genealogy of Christ, in the ca- thedral of Seville, called La generation. VARICOSE VEINS, veins in a state of perma- nent and preternatural dilatation. The cause of the disease is to be looked for in some ob- struction to the return of blood through the affected veins. In some cases the obstruction may be in the heart itself ; old cases of heart disease, when the right side of the heart be- comes involved, are apt to be attended with a varicose condition of the veins of the neck. The pressure of tumors, aneurisms, &c., upon a large venous trunk, causes a varicose con- dition of its superficial branches ; the pressure of the enlarged uterus in pregnancy is a fertile source of varicose veins of the lower extremi- ties ; a varicose condition of the hiemorrhoidal veins constitutes piles, of those of tbe testicle varicocele. A varicose condition of the veins of the lower extremity, arising from certain occupations which demand the long continued maintenance of the upright posture, from re- peated pregnancies, and sometimes from weak- ness of the coats of the veins themselves, is an exceedingly common complaint. In the natural condition, by the frequently recurring contraction and relaxation of the voluntary muscles, the veins of the lower extremities are alternately filled and emptied. Walking about, or any ordinary form of exercise, therefore facilitates the movement of the blood in the veins. But where a single set of muscles only are kept in constant, and unvarying action, as in continued standing at a writing desk or a machine, the movement of the blood is ob- structed instead of being aided by the muscu- lar contraction, and it accordingly accumu- lates in the veins near the point of obstruc- tion, especially in the lower extremities, where it has to mount upward against the force of gravity. The veins are thus unnaturally dis- tended, and when their distention becomes so great that the edges of their opposite valves are drawn away from each other, the weight of the superincumbent column of blood is thrown upon that portion of the vein next be- low, and thus the affection extends, gradual- ly involving successive portions of the venous system. The veins are sometimes unequally . dilated, with knots and protuberances distrib- uted along their course. They are lengthened as well as dilated, their course becoming more tortuous. Sometimes the coats of the vein are thicker, sometimes thinner than natural, or both states may be present in the same vein. They are apt to cause more or less oedema of the affected limb, with a feeling of weight and fulness ; sometimes they give rise to or are accompanied by ulcerations which are difficult to heal ; occasionally, from gradual