MINGLING OF ORIENT AND OCCIDENT AT ALEXANDRIA. The most famous of all these Greek institutions, however, was the University of Alexandria, which gradually sapped Athens as a center of learning and became the intellectual capital of the world. The greatest library of manuscripts the world had ever known was collected together here. [11] It is said to have numbered over 700,000 volumes. These included Greek, Jewish, Egyptian, and Oriental works. In connection with the library was the museum, where men of letters and investigators were supported at royal expense. These two constituted an institution so like a university that it has been given that name. Alexandria became not only a great center of learning, but, still more important, the chief mingling place for Greek, Jew, Egyptian, Roman, and Oriental, and here Greek philosophy, Hebrew and Christian religion, and Oriental faith and philosophy met and mixed. It was this mingled civilization and culture, all tinged through and through with the Greek, with which the Romans came in contact as they pushed their conquering armies into the eastern Mediterranean (R. 10). [Illustration: FIG. 15. THE KNOWN WORLD ABOUT 150 A.D. A map by Ptolemy, geographer and astronomer at Alexandria. Compare this with the map on page 4, and note the progress in geographical discovery which had been made during the intervening centuries.] CHARACTER OF ALEXANDRIAN LEARNING. The great advances in knowledge made at Alexandria were in mathematics, geography, and science. The method of scientific investigation worked out by Aristotle at Athens was introduced and used. Instead of speculating as to phenomena and causes, as had been the earlier Greek practice, observation and experiment now became the rule. Euclid (c. 323-283 B.C.) opened a school at Alexandria as early as 300 B.C., and there worked out the geometry which is still used in our schools. Archimedes (287-212 B.C.), who studied under Euclid, made many important discoveries and advances in mechanics and physics. Eratosthenes (226-196 B.C.), librarian at Alexandria, is famous as a geographer [12] and astronomer, and made some studies in geology as well. Ptolemy (b.?; d. 168 A.D.) here completed his Mechanism of the Heavens (_Syntaxis_) in 138 A.D., and this became the standard astronomy in Europe for nearly fifteen hundred years, while his geography was used in the schools until well into the fifteenth century. The map of the known world, shown in Figure 15, was made by him. Hipparcus, the Newton of the Greeks, studied the heavens both at Alexandria and Rhodes, and counted the stars and arranged them in constellations. Many advances also were made in the study of medicine, the Alexandrian schools having charts, models, and dissecting rooms for the study of the human body, The functions of the brain, nerves, and heart were worked out there.