HIPPURIC ACID (Gr. [Greek: hippos], horse, [Greek: ouron], urine), benzoyl glycocoll or benzoyl amidoacetic acid, C9H9NO3 or C6H5CO.NH.CH2.CO2H, an organic acid found in the urine of horses and other herbivorae. It is excreted when many aromatic compounds, such as benzoic acid and toluene, are taken internally. J. v. Liebig in 1829 showed that it differed from benzoic acid, and in 1839 determined its constitution, while in 1853 V. Dessaignes (_Ann._ 87, p. 325) synthesized it by acting with benzoyl chloride on zinc glycocollide. It is also formed by heating benzoic anhydride with glycocoll (Th. Curtius, _Ber._, 1884, 17, p. 1662), and by heating benzamide with monochloracetic acid. It crystallizes in rhombic prisms which are readily soluble in hot water, melt at 187 deg. C. and decompose at about 240 deg. C. It is readily hydrolysed by hot caustic alkalis to benzoic acid and glycocoll. Nitrous acid converts it into benzoyl glycollic acid, C6H5CO.O.CH2.CO2H. Its ethyl ester reacts with hydrazine to form hippuryl hydrazine, C6H5CO.NH.CH2.CO.NH.NH2, which was used by Curtius for the preparation of azoimide (q.v.). HIPURNIAS, a tribe of South American Indians, 2000 or 3000 in number, living on the river Purus, western Brazil. Their houses are long, low and narrow: the side walls and roof are one, poles being fixed in the ground and then bent together so as to meet and form a pointed arch for the cross-sections. They use small bark canoes. Their chief weapons are poisoned arrows. They have a native god called Guintiniri. HIRA, the capital of an Arabian kingdom, founded in the 2nd century A.D., on the western edge of Irak, was situated at 32 deg. N., 44 deg. 20' E., about 4 m. S.E. of modern Nejef, by the Sa'ade canal, on the shore of the Bahr Nejef or Assyrium Stagnum. Its kings governed the western shore of the lower Euphrates and of the Persian Gulf, their kingdom extending inland to the confines of the Nejd. This Lakhmid kingdom was more or less dependent, during the four centuries of its existence, on the Sassanian empire, to which it formed a sort of buffer state towards Arabia. After the battle of Kadesiya and the founding of Kufa by the Arabs, Hira lost its importance and fell into decay. The ruin mounds covering the ancient site, while extensive, are insignificant in appearance and give no indications of the existence of important buildings. HIRADO, an island belonging to Japan, 19(1/2) m. long and 6 m. wide, lying off the west coast of the province of Hizen, Kiushiu, in 33 deg. 15' N. and 129 deg. 25' E. It is celebrated as the site of the original Dutch factory--often erroneously written Firando--and as the place where one of the finest blue-and-white porcelains of Japan (_Hiradoyaki_) was produced in the 17th and 18th centuries. The kilns are still active.