46 On the supposed Changer 



to have changed, and deduct one half the supposed abate- 

 ment, still the result forbids us to believe the hypothesis. 

 If we suppose the heat of summer to have lessened in 

 the same proportion, as just philosophy requires us to do, 

 the summers formerly must have been intolerable ; no 

 animal could have subsisted under ten degrees of heat 

 beyond our present summer temperature. On which- 

 ever side we turn our eyes, we meet with insurmounta- 

 ble difficulties. 



From all I can discover, in regard to the seasons, in 

 ancient and modern times, I see no reason to conclude 

 Mdth Dr. Williams, that the heat of the earth is increas- 

 ing. It appears that all the alterations in a country, in 

 consequence of clearmg and cultivation, result only in 

 making a different distribution of heat and cold, mois- 

 ture and dry weather, among the several seasons. The 

 clearing of lands opens them to the sun, their moisture 

 is exhaled, they ai'e more heated in summer, but more 

 cold in winter near the surface ; the temperature be- 

 comes unsteady, and the seasons irregular. This is the 

 fact. A smaller degree of cold, if steady, will longer 

 preserve snow and ice, than a greater degree, under fre- 

 quent changes. Hence we solve the phenomenon, of 

 more constant ice and snow in the early ages ; which I 

 believe to have been the case. It was not the degree, 

 but the steadiness of the cold which produced this effect. 

 Every forest in America exhibits this phenomenon. We 

 have, in the cultivated districts, deep snow to-day, and 

 none to-morrow ; but the same quantity of snow falling 

 in the woods, lies there till spring. The same fact on a 

 larger scale, is observed in the ice of our rivers. This 

 will explain all the appearances of the seasons, in ancient 

 and modern times, without resorting to the unphilosoph- 

 ical hypothesis of a general increase of heat. 



