Hans Bulvai wrote:How did he conclude that the world was a sphere?
From the book:
In the books of the philosophers, who speculated about the condition of the world, it has been explained that the earth has a spherical shape . .
Others, better read than I, have told me that that the earth was a globe was common knowledge at that time. What wasn't understood was how large it was. Thus Columbus thought he could reach the Orient by sailing west out of Spain.
What especially impressed me about Khaldun was his knowledge that civilization ended at about 65˚ north. Consider:
“Man, as an animal, is indeed, a tropical animal. But man, as distinguished from animals, is not at his best in the tropics or very near them. His fight upward in civilization has coincided in part at least with his march northward over the earth into a cooler, clearer, more bracing air....
“Men at every period of history have been generally of the opinion that the ultimate limit of the northward spread of civilization had then at length been reached.
“...Tacitus probably knew as much as any of his contemporaries about the lands beyond the Alps, and was merely voicing the general opinion of his time and countrymen when he said that nobody could conceive that any one, unless forced by the stern necessity of war, would willingly leave the fertile shore of Africa or the plains of Italy for the country north of the Alps where the climate is as disagreeable as the soil is sterile. This was undoubtedly a truism of his time; but it is a fact of our time that many people live Paris and other parts of France by choice....
“It is human nature that we undervalue the distant and exaggerate the difficulties of the unknown...
“To the peoples of the centers of civilization the uncolonized North has been more or less remote geographically and almost infinitely remote from a cultural and historical point of view...
“On the basis of distance and misinformation the North has always been supposed to be dreadful and devoid of resources...
“...Tacitus was wrong when he said people would never by choice live as far north as France; the Moors of the Middle Ages were short-sighted when they undervalued the possibilities of Britain; it is strange that as astute a man as Franklin thought a small tropic isle like Guadaloupe commercially more valuable than Canada; Seward was wise in buying Alaska and Gladstone a simpleton to want to renounce Spitzbergen. But surely there must be somewhere the limit to Northward progress...
“We have not come to the northward limit of commercial progress...Corner lots in Rome were precious when the banks of the Thames had no value; the products of Canada were little beyond furs and fish when the British and French agreed in preferring Guadaloupe. ...But...times have changed. ...There is no northern boundary beyond which productive enterprise cannot go till North meets North on opposite shores of the Arctic Ocean as East has met West on the Pacific.
“If the average American...has ten ideas about the North, nine of them are wrong.
“...the most fundamentally wrong idea about the North is that...the polar regions are far colder in the coldest part of winter than any countries that are now inhabited by the average civilized European or American.
“A complement of the idea that the North is dreadfully cold in winter is the notion that it is also cold through the entire summer. It is possible to maintain that the winters are dreadfully cold, but only by agreeing that the winters of northern Vermont and Saranac Lake and Minnesota and Montana are also dreadfully cold. ...Five miles from the ocean at Point Barrow the temperature probably seldom if ever rises above 75º in the shade, which is ten degrees colder than the similar record for Fort Bragg, California, both places being at sea level and near the sea. But fifty miles inland in California gives you a temperature of 110º in the shade, and a hundred miles inland in Alaska will give a temperature approaching 100º in the shade....
“...we come next to a consideration of the length of the seasons. It is true, generally speaking, that the farther north you go in the northern hemisphere the longer the winter and the shorter the summer. ...A Sicilian may think that a winter of three months’ length is intolerable and if he insists that is is intolerable you can’t very well argue with him, but you can at least prove to him that numerous prosperous people live in a climate where there are three months of winter. ...in Winnipeg you will in turn meet people who say that while five or six months of winter is no serious handicap to economic development, nine months of winter would be...intolerable. ...The argument is of the same nature and is its essence no more tenable than that of the Sicilian who thinks that even the shortest winter is unbearable. ...
“That the ground in the polar regions is always covered with snow...is another of the widely-spread wrong notions. ... Even in the tropics there is permanent snow on the mountain tops if the mountains are high, and even in the remotest arctic regions the snow all disappears from the land in summer.
“A corollary of the idea that the North is covered with snow even in summer is the one that it is a region of heavy snowfall. This is far from being true.
“...In the development of the (north) country these (false notions) will prove a drawback... China’s wall of masonry was never a very efficient barrier. A wall of misinformation is more effective, more difficult to tear down."
—excerpted from The Northward Course of Empire, Vilhjalmur Stefansson, Macmillan, 1924
"The jawbone of an ass is just as dangerous a weapon today as in Sampson's time."
--- Richard Nixon
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"I consider looseness with words no less of a defect than looseness of the bowels."
—John Calvin