In the extremes of winter and summer, when the weather is either extraordinarily cold or hot, I confess to experiencing a peculiar sense of helplessness and vague uneasiness. I have a feeling that a trifling additional rise or fall of temperature, such as might be caused by any slight hitch in the machinery of the universe, would quite crowd mankind out of existence. To be sure, the hitch never has occurred, but what if it should? Conscious that I have about reached the limit of my own endurance, the thought of the bare contingency is unpleasant enough to cause a feeling of relief, not altogether physical, when the rising or falling mercury begins to turn. The consciousness how wholly by sufferance it is that man exists at all on the earth is rather forcibly borne in upon the mind at such times. The spaces above and below zero are indefinite.