They measure the earth.  These ideas, which indeed are not peculiar to Mohammedanism, but are entertained by all men in a certain stage of their intellectual development as religious revelations, were very quickly exchanged by the more advanced Mohammedans for others scientifically correct.  Yet, as has been the case in Christian countries, the advance was not made without resistance on the part of the defenders of revealed truth.  Thus when Al-Mamun, having become acquainted with the globular form of the earth, gave orders to his mathematicians and astronomers to measure a degree of a great circle upon it, Takyuddin, one of the most celebrated doctors of divinity of that time, denounced the wicked khalif, declaring that God would assuredly punish him for presumptuously interrupting the devotions of the faithful by encouraging and diffusing a false and atheistical philosophy among them.  Al-Mamun, however, persisted.  On the shores of the Red Sea, in the plains of Shinar, by the aid of an astrolabe, the elevation of the pole above the horizon was determined at two stations on the same meridian, exactly one degree apart.  The distance between the two stations was then measured, and found to be two hundred thousand Hashemite cubits; this gave for the entire circumference of the earth about twenty-four thousand of our miles, a determination not far from the truth.  But, since the spherical form could not be positively asserted from one such measurement, the khalif caused another to be made near Cufa in Mesopotamia.  His astronomers divided themselves into two parties, and, starting from a given point, each party measured an arc of one degree, the one northward, the other southward.  Their result is given in cubits.  If the cubit employed was that known as the royal cubit, the length of a degree was ascertained within one-third of a mile of its true value.  From these measures the khalif concluded that the globular form was established.

Their passion for science.  It is remarkable how quickly the ferocious fanaticism of the Saracens was transformed into a passion for intellectual pursuits.  At first the Koran was an obstacle to literature and science.  Mohammed had extolled it as the grandest of all compositions, and had adduced its unapproachable excellence as a proof of his divine mission.  But, in little more than twenty years after his death, the experience that had been acquired in Syria, Persia, Asia Minor, Egypt, had produced a striking effect, and Ali the khalif reigning at that time, avowedly encouraged all kinds of literary pursuits.  Moawyah, the founder of the Ommiade dynasty, who followed in 661, revolutionized the government.  It had been elective, he made it hereditary.  He removed its seat from Medina to a more central position at Damascus, and entered on a career of luxury and magnificence.  He broke the bonds of a stern fanaticism, and put himself forth as a cultivator and patron of letters.  Thirty years had wrought a wonderful change.  A Persian satrap who had occasion to pay homage to Omar, the second khalif, found him asleep among the beggars on the steps of the Mosque of Medina; but foreign envoys who had occasion to seek Moawyah, the sixth khalif, were presented to him in a magnificent palace, decorated with exquisite arabesques, and adorned with flower-gardens and fountains.