Left a page from a better known manuscript of Sijistani on cosmography.
(On the Proof of Prophecies) (1000)
from Khurasan and Sijistan in Iran.
Taken from: www.amana.org
Paul E. Walker : Early Philosophical Shiis.....
Also called Abu Ya'qub al Sijistani, Ishaq ibn Ahmad : Hadha Kitab Ithbat al-Nubuwat fi al-Haqa'iq / Ithbat al-nubuwa
By the ninth century, the Fatimids (Ismaelis) had organized a secret movement called al-da'wa (the mission). The aim was to uproot the Abbasids. The regions outside the Fatimid dominions, were divided into twelve jaziras or "islands" for da'wa purposes, each jazira representing a separate da'wa region. Delineated on the basis of a combination of geographic and ethnographic considerations, the "islands", collectively designated as "the islands of the earth" (jaza'ir al-ard), included Rum (Byzantine), Daylam (this is in Persia), Sind, Hind, Sin (China), and the regions inhabited by Arabs, Nubians, Khazars, Slavs (Saqaliba), Berbers, Zanj, and Habash.
The nations or territories that have never had a prophet are Sind, Hind (India), Sin (China), the Zanj, the Turks, the Khazars, and the Slavs. Only the region bounded by Mekka in the south and Syria and Jerusalem in the north has been the scene of prophecy.