i66 Humphreys: meteorol,ogical paradoxes 



The storage of heat in the earth while the days are long, 

 its gradual delivery back to the surface while the daily supply 

 from the sun is comparatively small; and the poleward drift 

 of warm water at all seasons, together produce, as explained, 

 the paradoxical result so admirably expressed by the proverb, 



As the days grow longer 



The cold grows stronger. 



AS THE NIGHTS GROW I.ONGER THE HEAT GROWS STRONGER 



It will be recognized at once that this paradox is only the 

 counterpart of the one just discussed, and that it must also have 

 .substantially the same explanation. 



As the days continue to grow longer after the time of mini- 

 mum temperature, it is clear that from then on for several 

 months the earth's gain of heat must be at a faster rate than its 

 loss — that, in terms of the above explanatory hypothesis, the 

 effective temperature of the shell is T and that of the enclosed 

 object T — t. Under these conditions the earth, because of its 

 large but finite heat capacity, must continue to slowly grow 

 warmer until the incoming radiation has become less, that is, 

 until the nights have grown perceptibly longer. 



This lag, the lag of maximum temperature after the summer 

 solstice, is also, like the lag of minimum temperature after the 

 winter solstice, a function of location; generally least in the 

 interior of continents and greatest on islands and near coasts 

 whose prec^ailing winds are on-shore. 



AS THE SUN DESCENDS THE TEMPERATURE ASCENDS 



By this paradoxical expression it is only meant to state tersely 

 the well-known fact that the warmest time of the day is not when 

 the sun is on the meridian, or when insolation is greatest, but 

 sometime in the afternoon when the sun has descended con- 

 siderably from its maximum elevation. As everyone knows, 

 night cooling reaches its greatest effect, on the average, just 

 after daybreak. Hence, as the sun ascends the temperatures 

 of the warming surface of the earth and of the lower air lag be- 

 hind equilibrium with the incoming radiation, and continue to 

 do so until the intensity of the insolation has passed well beyond 



