Glaciology in the Sixteenth Century. The following passage is translated from Sebastian Münster's Cosmographia Universalis (Basel, 1543):

What is understood of Glaciers. Glaciers, though not mine nor metal, yet resemble pure crystal in clarity, and are found usually to the south on the highest and wildest of peaks, which are called snowmountains. Yet it is neither snow nor ice, but rather a hardened ice that never melts on the tops of the mountains. Lying there for two or three thousand years, it has become almost as hard as stone. And so, when a piece falls into a valley, it remains lying for a long time before turning into water, even in the great heat of summer or the glare of the sun. It is also so constituted that it purges and cleanses itself, so that in it no particles, sand or stone, large or small, remain. It tolerates none of these and becomes clear as crystal. It is almost unfathomably deep, frequently forms great crevasses and chasms, most difficult to cross, even by hunters, especially when covered with snow. In many places the gaping cracks are three or four hundred fathoms deep, almost bottomless. In summertime the beginning of a crack produces as fearful a sound as if the crust of the earth were broken. The hunters hang flesh and beast in them in summer so that it will freeze and preserve until a profitable time to sell. For the peasants the glacier also serves as medicine in severe illnesses, namely in dysentery, sunstroke and acute fevers, all of which are diseases of heat. They even say that glacier water is healthful under many circumstances. In summer it is extremely cold, turbid and gray as if saturated with ashes, and comes pouring out of the valleys in flooded brooks. In some places it falls from high cliffs; notably between St. Maurice and Martigny [the Pissevache waterfall], it pours from a lofty rock, fearsome to see. There is such frigidity in a glacier that one can make warm wine quite cold with but a bit of ice. In 1546, on the fourth day of August, I observed at the Furca that it was two or three spear-lengths thick, a crossbowshot wide, and I could see no end to its length; on which account it created an impression of awe. A piece the size of a house had just fallen, which made the prospect even more terrifying, and a stream with water and ice poured out of it so that I could not ride my horse across a bridge. And this water was the source of the Rhone. Not far from this glacier a large spring gushed forth on the mountain, which someone showed me as the source of the Rhone. Everywhere from the mountains, waters run into this primary stream which soon forms the Rhone, falling over mountain and cliff with such roaring that one can scarcely hear the words of his companion. And this goes on and on until one comes to Brigue, one waterfall after another, and often the water falling from on high in foam and spray. Glaciers are known to exist on the other side of the Furca, and clinging to even higher mountains which adjoin the Furca. At the source of the Rhone, on the mountainside one can dig out masses of crystals, and many marmots run about, which are not left unharmed by men. It is quite cold on the Furca because of the perpetual snow and ice found there."

J.M.T.