ISOPERIMETRICAL 209 ISRAELS initiated the offensive. The Austrians, reinforced by troops from the Russian front, and by large contingents of Ger- mans, began a determined effort to drive the Italians back into Italy. The battle on the Isonzo front w^as really only one phase of the fighting along the whole Austrian-Italian line. For several days the Italians suc- ceeded in holding the onrushes of the Teutons in check, but as reinforcements continued streaming in, the Italian line began gradually to sag, v^'ith breaks ap- pearing here and there. On Oct. 28, 1917, Gorizia again fell into the hands of the Austrians. Violent storms and heavy rains broke over the Isonzo district, but without any notice- able decrease in the energy of the Austrian-German attacks. Thousands of Itr.lians were taken prisoners and much war material had to be abandoned. On Oct. 29, 1917, Udine was taken by the Teutons, Cividale had been taken the day before. Both towns were of great strategic importance, Udine being a railroad junction. The Austrian drive continued, with further disaster to the Italians. They retreated, until they made their last and successful stand along the Piave (q. r.), but with the loss of Cividale and Udine the battles on the Isonzo came to an end, to be continued in the battles of the Piave. The Isonzo was now, for the time being, almost entirely in the hands of the Austrians. ISOPERIMETRICAL, in geometry, a term applied to figures which have equal circumferences or perimeters, ISOPODA (I-sop'6-da), in zoology, an order of Crustaceans, division Thor- acipoda, legion Edriophthalmia. The body is composed of seven segments, as a rule nearly equal in size. The legs, which are seven pairs, are almost of the same length. They are fitted for walking, swimming, or adhering as para- sites. The posterior (abdominal) ap- pendages are converted into leaf-like respiratory apparatus. The heart is near the tail. The common wood louse is a well-known example of Isopoda. ISOTHERMAL LINES, lines on a globe or map passing over places in which the mean general temperature is the same. Humboldt first generalized the observations and collected the facts bearing on isothermal lines. ISOTROPISM, physical homogeneity or amorphism; identity of elastic forces of propagation of vibration (light, heat, sound), or identity of susceptibility to magnetization, in all directions. ISPAHAN (is-pa-han'), a city of Persia, and formerly the capital of that empire. It is situated in the province Irak-Ajemi, of which it is the capital. It stands in the midst of an extensive plain, abundantly watered by the Zen- derood, a river about 600 feet broad; and is surrounded by groves, avenues, and spreading orchards. Within its limits the city comprises one vast .suc- cession of superb mosques, immense bazaars, marble palaces, canals, foun- tains, and gardens. The manufacture of all kinds of woven fabrics, from the most costly gold brocade of figured vel- vet to the most ordinary calico or coarse cotton, is pursued on an extensive scale; many hands are also employed in making trinkets and jewelry, paper, papier- mache goods, arms, steel sword blades, glass and earthenware. Ispahan is the chief commercial emporium of Persia, and on the great line of communication between India, Cabul, and China on the E. and Turkey, Egypt, and the Mediter- ranean on the W. The inhabitants are considered the best artificers in Persia, and education is very general. Ispahan, under the caliphs of Bagdad, became the capital of Irak, and under Shah Abbas the metropolis of Persia. In 1722 Ispa- han was reduced by the Afghans, and in 1727 was retaken by Nadir Shah, who, however, took no steps to restore it to its ancient glory. Within the last 100 years the capital has been transferred to Teheran, and Ispahan has gradually fallen into a state of decay from which even its commercial importance has not been able to redeem it. Pop. (1918) 80,000. ISRAEL, the name divinely given to Jacob during the scene at Peniel or Penuel as a memorial that, as a prince, he had power with God and with men and had prevailed (Gen. xxxii:28). Also the Jewish people; a contraction for Children of Israel or House of Israel (Hosea xi:l). See Jews. Also a re- ligious sect which appeared for the first time in England in 1883. ISRAELITES. See JEWS. ISRAELS, JOSEF, a Dutch artist; born in Groningen in 1824. He studied at Amsterdam under Pieneman and Kruseman, and in Paris under Picot and Henri Scheffer. In 1855 his "Wil- liam, Prince of Orange, opposing the Decree of the King of Spain" attracted attention in the Exposition Universelle. In 1867 his celebrated "Interior of the Orphan Asylum at Katwijk" gained for him a third-class medal and the ribbon of the Legion of Honor; and eight years
