Page:Smith - Number Stories of Long ago (1919).djvu/59

NUMBER STORIES Long after Gupta died, and about a thousand years ago, someone had the wisdom to invent the zero, and after that it was easy to write numbers as we write them to-day.

About the time that the zero was invented there was born in the country near the Caspian Sea a boy whose parents named him after Mohammed (mṓ hăm'ĕd), the great religious leader of the Arabs.

Little Mohammed was a very bright boy, and Moses his father let him study with one of those wise men who watched the stars and thus told the time, for clocks and watches were then unknown.

Mohammed became so well known as a scholar that while still a young man he was called to Bagdad (båg däd') to be the caliph’s (kā'lĭf) astronomer. The caliphs were the kings of the country about the Tigris (tī'grĭs) River, and many stories are told about them in the Arabian Nights Tales. These tales describe Bagdad at about the time that our 38