If it be true that the Saracens burned the Alexandrian library, it must be considered that this was the act of an uneducated general and the vengeance of the soldiery after a terrible siege, rather than the deliberate policy of the government. Within twenty-five years from the death of Mahomet the Caliphs had become famous for their patronage of learning. Ali, the fourth Caliph and son-in-law of Mahomet, used to say, "The world is sustained by four things only: the prayers of the good, the learning of the wise, the justice of the great, and the valor of the brave." This sentiment was echoed and re-echoed until it became an honored maxim in the minds of millions. Under the influence of Jewish, Nestorian and Saracen teachers the manners of the Saracens became more polished and their thoughts more elevated. They made conquests in the realms of science, literature and the arts as quickly as in the provinces of the Roman empire. For example, Almansor, who reigned as Caliph from A. D. 753 to 775, established the University of Bagdad, and endowed it with two hundred thousand pieces of gold, and an annual revenue of fifteen thousand dinars, equal in commercial value to one hundred and twenty thousand dollars of our money. He invited thither learned men from every land, irrespective of their religious opinions. By these men were founded celebrated schools of mathematics, astronomy, chemistry, medicine, law and languages. {36} His grand-son, Haroun-al-Raschid, ordered in A. D. 786, that a public school should be attached to every mosque in his dominions. This was more than seven hundred years before the establishment of the famous parish schools of Scotland. The Caliph-al-Mamun, in A. D. 813, founded the great medical college of Cairo, which required students to pass a rigid examination before receiving authority to enter on the practice of their profession. At this college we have the first account of dissecting human bodies for the purpose of ascertaining the nature and locality of diseases, and the first circulating library for students. These books were bound according to the modern form, which then began to be used among the Saracens in place of the ancient form of the scroll. By the means just mentioned, the ancient sciences were greatly extended and new ones introduced. To the Saracens we are indebted for our present system of arithmetical notation. If, for example, we wish to multiply 1882 by 125 and then attempt it by the ancient method MDCCCLXXXII., multiplied by CXXV., we shall soon perceive the vast superiority of the Arabic system over that formerly in use. No wonder, then that under the ancient system those who were engaged in solving difficult mathematical problems were frequently styled "sweating calculators."