Describes how COPD, or chronic obstructive pulmonary disease, is a progressive disease that makes it hard to breathe. Details the symptoms of COPD. Shows how the disease works in the lungs. Explains how progress of the disease can be slowed.
Eratosthenes of Cyrene was a Greek mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria. He invented the discipline of geography, including the terminology used today. He is best known for being the first person to calculate the circumference of the Earth, which he did by comparing altitudes of the mid-day sun at two places a known North-South distance apart. His calculation was remarkably accurate. H
Eratosthenes, calculated the Earth's radius around 1700 BC.He used the distance between two cities and the angle of the sun's rays made at midsummer at noon. His measurement turned out to be 15 percent too large, but still impressive, considering it was done over 2600 years ago.