This idea of a connection between labour (friction) and force (motion), and this explanation of the possible origin of volcanoes are surprising in the thirteenth century, and seem to bring the author centuries in advance of his time; we here have germs of the theory of the conservation of energy.
His statements about Greenland are remarkable for their sober trustworthiness. He gives the first description of its inland ice:
"But since you asked whether the land is thawed or not, or whether it is covered with ice like the sea, you must know that there are small portions of the land which are thawed, but all the rest is covered with ice, and the people do not know whether the country is large or small, since all the mountains and valleys are covered with ice, so that no one can find his way in. But in reality it must be that there is a way, either in those valleys that lie between the mountains, or along the shores, so that animals can find a way, for otherwise animals cannot come there from other countries, unless they find a way through the ice and find the land thawed. But men have often tried to go up the country, upon the highest mountains in various places, to look around them, to see whether they could find any part that was thawed and habitable, but they have not found any such, except where people are now living, and that is but little along the shore itself."
[Illustration: Norwegian MS. of the Gulathings law. Fourteenth century]
This, as we see, is an extremely happy description of the mighty ice-sheet. He also describes the climate of the country, both the fine weather that often occurs in summer, and its usually inclement character, which causes so small a proportion of the country to be habitable.
[Sidenote: The glaciers of Greenland a pole of maximum cold]
"The land is cold, and the glacier [i.e., the great ice or inland ice] has this nature, that he sends out cold gusts which drive away the showers from his face, and he usually keeps his head bare. But often his near neighbours have to suffer for it, in that all other lands which lie in his neighbourhood get much bad weather from him, and all the cold blasts that he throws off fall upon them."
Though in simple and everyday words, this really expresses the idea that Greenland and the neighbouring regions are disproportionately cold, and that, in part at any rate, this is due to the glaciers of Greenland, which have a refrigerating effect (as an anticyclonic pole of maximum cold). This is to a certain degree correct. In crossing Greenland in 1888 we found that a pole of cold [anticyclone] lies over the inland ice, which gives off cold air. Scientific greatness does not always depend on erudition or acute learned combinations; it is just as often the result of a sound common-sense.