Note 11 — Chapter XXXII

The temperature of the air at the North Pole has furnished a fruitful theme of speculation, both in connection with the influence of the sea and of the sun. I have before me a highly instructive paper on the climate of the North Pole, read before the Royal Geographical Society of London, April 10th, 1865, by W. E. Hickson, Esq., from which I extract the following:—

"It had always been supposed that the immediate areas of the Poles must be the coldest regions of the globe, because the farthest points from the equator. Hence the argument that the higher the latitude the greater must be the difficulties and dangers of navigation. Quite an opposite opinion, however, had begun to prevail among meteorologists on the publication, in 1817, of the Isothermal system of Alexander Von Humboldt, which showed that distance from the equator is no rule for cold, as the equator is not a parallel of maximum heat. The line of maximum heat crosses the Greenwich meridian, in Africa, fifteen degrees north of the equator, and rises, to the eastward, five degrees higher, running along the southern edge of the Desert of Sahara. In 1821, Sir David Brewster pointed out, in a paper on the mean temperature of the globe, the probability of the thermometer being found to range ten degrees higher at the Pole than in some other parts of the Arctic Circle. No new facts have since been discovered to invalidate this conclusion—many, on the contrary, have come to light tending to confirm it."