Fayum
2 of the 7 encyclopedias on this shelf carry an entry for Fayum. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
or Fayoum, a district of ancient Egypt lying west of the Nile and southwest of Cairo. It is a circular basin about thirty miles in diameter. It lies below the surface of the Libyan desert, and is connected with the valley of the Nile by a narrow pass threaded by an ancient canal. It was and is well watered. It contains about 500 square miles and sustains a population of a quarter of a million persons. Lake Birket lies in the northwestern part. Herodotus described a vast reservoir thirty miles in circumference, used to store the waters of the Nile, Lake Moeris, he called it. The closest examination fails to locate the embankment of any such lake satisfactorily. It is believed he may have visited the country in a time of overflow and have been deceived by local dikes. The soil produces crops of wheat, flax, hemp, rice, cotton, and sugar-cane; orchard fruits, including oranges, peaches, pomegranates, olives, figs, and grapes are abundant. Roses grow luxuriantly. Garden vegetables are plentiful. Archaeological finds of great antiquity have been located in the Fayum. A famous palace, known as the Labyrinth, has given up many treasures. See Egypt ; Nile
Collier's New Encyclopedia (1921)
FAYOUM, or FAIOUM (fa-yoom'), a famous valley and province of central Egypt, anciently the name of Arsinoë, and stretching out into the desert, which almost entirely surrounds it. In extent, its length may be taken at 40 miles by a width of 30. It is the most fertile of the Egyptian provinces and produces dhurra, rye, barley, flax, cotton, sugar, grapes, olives, figs, etc. Near the capital (Medinet-el-Fayum) large quantities of roses are cultivated, Vol. IV-Cyc-H and are converted into rose water which is highly esteemed. The land capable of cultivation in Fayum is about 493 square miles. Manufactures woolen, linen, and cotton goods. In ancient times, the Fayum contained the artificial lake MOERIS (q. v.) and a famous labyrinth.