Library Eusebius of Caesarea Preparation for the Gospel
Book 9, Chapter 35
'TIMOCHARES, in his Life of Antiochus, says that Jerusalem has a circuit of forty furlongs, and is difficult to take, being shut in on all sides by abrupt ravines: and that the whole city is flooded with streams of water, so that even the gardens are irrigated by waters which flow off from the city. But the country from the city as far as forty furlongs is without water: but beyond the forty furlongs again it is well watered.'
English translation by E. H. Gifford, Eusebii Pamphili Evangelicae Praeparationis Libri XV (Oxford, 1903). Public domain. Digital text via Roger Pearse / tertullian.org.