if add to the 448 millions of human
There is no blind fatality about heat and cold. The extreme North of Canada and Alaska is not inhabited in any regular way, although no temperature below - S4° Fahrenheit or - 47° Centigrade has been recorded there. But near Havre (Montana, U.S.A.), much further to the south, the thermometer has gone down to ~ 68° Fahrenheit, and not far off in Northern Dakota the winter is as severe as in any Arctic region, yet experience proves that men can live in these parts quite well. If we take account of the fact that for a whole year the number of hours of sunshine is greater in the North than in the temperate regions, where clouds and fogs intervene so as. practically to restrict its theoretical duration, we can easily see that it is not the laws of climate only that determine the uninhabited condition of so much of the Arctic region.