HERON, called the younger, to distinguish him from his namesake of Alexandria, was, like him, a mathematician and natural philosopher. By some he is supposed to have flourished in the first half of the 7th century A.D. ; by others, with more probability, to have lived at Constantinople in the 10th century. He wrote a treatise on Besieging Engines which still exists, and another on the Construction of Sun-dials, which is now lost. Some mathematical writings assigned to him should perhaps be referred to Heron the elder (sec lllemoires Presentes a l'Acadi:mie des Inscriptions, Pre s6rie, tome iv., Paris, 1854).