HIERRO, or FERRO  , an island in the Atlantic Ocean, forming part of the Spanish archipelago of the Canary Islands (q.v.) . Pop . (1900) 65o8; area 107 sq. m . Hierro, the most westerly and the smallest island of the group, is somewhat crescent-shaped . Its length is about 18 m., its greatest breadth about 15 m., and its circumference 50 M . It lies 92 M . W.S.W. of Teneriffe . Its coast is bound by high, steep rocks, which only admit of one harbour, but the interior is tolerably level . Its hill-tops in winter are sometimes wrapped in snow . Better and more abundant grass grows here than on any of the other islands . Hierro is exposed to westerly gales which frequently inflict great damage . Fresh water is scarce, but there is a sulphurous spring, with a temperature of 102° Fahr .

The once celebrated and almost sacred Til

tree, which was reputed to be always distilling water in great abundance from its leaves, no longer exists . Only a small part of the cultivable land is under tillage, the inhabitants being principally employed in pasturage . Valverde (pop. about 3000) is the principal town . Geographers were formerly in the habit of measuring all longitudes from Ferro, the most westerly land known to them . The longitude assigned at first has, however, turned out to be erroneous; and the so-called " Longitude of Ferro " does not coincide with the actual longitude of the island .