now lost work of Marinus of Tyre had already been translated. Almamoun
drew to his Court all the chief "mathematicians" or philosophers of
Islam, such as Mohammed Al-Kharizmy, Alfergany, and Solyman the
merchant. Further he built two observatories, one at Bagdad, one at
Damascus, and procured a chart fixing the latitude and longitude of
every place known to him or his savants. Al-Kharizmy interpolated the
new Arabic Ptolemy with additions from the Sanscrit, and made some use
of Indian trigonometry. Alfergany wrote the first Arab treatise on the
Astrolabe and adopted the Greek division of the seven Climates to the
new learning. Solyman, at the time of closest intercourse between
China, India, and the Caliphate, travelled in every country of the
Further East, sailed in the "Sea of Pitchy Darkness" on the east coast
of Asia, and by his voyages became the prototype of Sinbad the Sailor.

The impulse given by Almamoun did not die with him. About 850 Alkendy
made a fresh version of Ptolemy; as early as 840 the Caliph Vatek-Billah
sent to explore the countries of Central Asia, and his results have been
preserved by Edrisi. A few years later (_c._ 890) Ibn-Khordadbeh, "Son
of the Magi," described the principal trade-routes, the Indian by the
Red Sea from Djeddah to Scinde, the Russian by the Volga and North
Caspian, the Persian by way of Balkh to China. It was by this last that
some have thought the envoys of the English King Alfred went in 883,
till they turned south to seek India and the Christians of San Thomé.

The early scientific movement in Islam reached its height in Albateny
and Massoudy at the beginning of the tenth century. The former
determined, more exactly than before, various problems of astronomical
geography.[12] The latter visited every country from Further India to
Spain;--even China and Madagascar seem to have been within the compass
of his later travels; and his voyages in the Indian Ocean bring us to