218 Dr Forry on the Climate of the United States. 



continued into the southern hemisphere, traverses the Pacific 

 Ocean, the theory is again at fault ; for the laws of climate 

 resulting from physical geography, place it about 30° farther 

 east on the continent of South America ; and in the Old World, 

 the coldest meridian, if continued into the southern hemi- 

 sphere, instead of being that of 100°, will be found either in 

 Africa or New Holland. But the circumstance of the migra- 

 tion of these meridians, makes still greater demands upon our 

 credulity, inasmuch as it was directly counter to the well- 

 established principle, that any alteration in the climate of 

 a locality supposes a corresponding alteration in its physi- 

 cal features. That there Sive poles of greatest cold correspond- 

 ing to the terrestrial magnetic poles, as distinguished from 

 the poles of rotation, is, however, quite probable. 



Does the climate of a locality, in a series of years, undergo 

 any permanent changes ? The question has been much de- 

 bated, whether the temperature of the cnist of the earth or 

 of the incumbent atmosphere, has undergone any perceptible 

 changes since the earliest records, either from the efforts of 

 men in clearing away forests, draining marshes, and culti- 

 vating the ground, or from other causes. So general is the 

 opinion that the temperature of the winter season in northern 

 latitudes, has become higher in modern than it was in an- 

 cient times, that it has been regarded as an admitted fact. 

 Among the writers of reputation who have adopted and 

 maintained this opinion, are the Abbe Du Bos, Buffon, Hume, 

 Gibbon, Volney ; and in our own counti-y, Jefferson, Wil- 

 liams, and Dr Holyoke. By them it is alleged that the winters 

 of the south of Europe, in the time of the Roman emperors, 

 were, according to the concurring testimony of many authors, 

 much more severe than now. In proof of this assertion, they 

 quote many passages from the ancient authors, Juvenal, 

 Virgil, Ovid, &c. ; and in regard to Gaul and Germany, the 

 writings of Csesar, Diodorus Siculus, &c. 



Gibbon in his " Decline and Fall of the Roman Empire," 

 has contributed perhaps more than any other to perpetuate 

 the afl&i*mative of this opinion. The ignorance of the great 

 laws of climate betrayed by him in the observation, that 

 " Canada, at this day, is an exact picture of ancient Germany, ^^ 



