Friday, November 22, 2013 – 10:20 AM
Earlier this year, one of youse recommended that I read Lloyd Brown’s The Story of Maps. First, thank you! I enjoyed it.
One of the things that really struck me was how closely held maps were for most of human history. «They were much more than an aid to navigation,» Brown writes. «They were, in effect, the key to empire, the way to wealth. As such, their development in the early stages was shrouded in mystery, for the way to wealth is seldom shared. There is no doubt that the complete disappearance of all charts from the earliest period is due to their secret nature and to their importance as political and economic weapons of the highest order.»
Reading that made me wonder if military historians should consider the invention of reliable maps as a revolution in military affairs, akin to the invention of the stirrup and the weaponization of gunpowder. If so, which nations benefited? First, it appears from reading Brown, were the Phoenicians — though, he says, none of their maps has survived.
Monday, November 25, 2013 – 10:29 AM
Eratosthenes calculated not only that the earth was round, but also that it was roughly 24,000 miles in circumference.
He did this with a brilliant insight followed by a simple bit of arithmetic: He began with the difference between the angular height of the sun from Alexandria (where he was the librarian) and from Syene (AKA Aswan), a city about 500 miles south of it. On the day of the solstice, the difference was just under 7.5 degrees, or one-fiftieth of a circle, which of course is 360 degrees. So, doing the math, he figured that 7.5 was to 360 as 500 was to X, which made X, the circumference of the world, roughly 25,000 miles. Pretty cool — and very close to the actual measurement of 24,901 miles at the equator.
Tuesday, November 26, 2013 – 10:48 AM
As I wrote earlier, for most of human history, maps and charts were closely held state or commercial secrets. Making maps publicly available didn’t really start occurring until the 19th century, Brown writes. It was only later that century that «the science of cartography reached maturity,» he adds.
But even decades later, at the start of World War II, he relates, much of the world was poorly mapped. This touched off a search for forgotten maps in archives that might help fill in the blanks. «In the absence of anything better, a map published in 1880 or even 1860 was to be treated with respect,» Brown writes. «Historical cartography suddenly became current and highly desirable.»