Dr FoiTy on the Climate of the United States. 217 



situated near a large body of water, derives its uniform cli- 

 mate from its position near the western coast of the continent. 



A decision of this long-mooted question is thus presented, 

 illustrating the ancient axiom, that truth is never found in 

 extremes. Kirwan, however, was somewhat nearer the truth 

 than Humboldt. As regards any credit that may pertain to 

 this explanation — a deduction that the writer made several 

 years ago — he considers it exclusively his own. 



Reference may be made to the " well-established fact of 

 meridians of greatest cold,'''' so called by Ti-aill in the Encyclo- 

 paedia Britannica. " The remarkable fact," he says, " of the 

 influence of longitude on temperatui-e, leads to the conclusion, 

 that on each side of the equator there are two meridians, under 

 which the mean temperature is lowest. These have been 

 termed, by Sir David Brewster, the cold meridians, and their 

 extremities are the poles of greatest cold. The portions of these 

 in the northern hemisphere may be approximated from recent 

 investigations ; and perhaps we shall not greatly err if we 

 assign the longitude of 95' west for the xlmerican, and of 100° 

 east for the Asiatic cold meridians. The apparent coincidence 

 of the cold meridians with the general directions of Hansteen's 

 lines of no variation, is perhaps more than accidental, when 

 we reflect that there seem to have been, in former ao-es, mi- 

 grations of the cold meridians eastward and westward, co- 

 incident, as far as we can judge from recorded changes of 

 climate in northern countries, with similar migrations of the 

 magnetic needle." 



This theory of cold meridians is at best extremely problem- 

 atical. If there is any truth in the laws of climate, as based 

 on physical geography, then is this theory no more than the 

 " baseless fabric of a vision." It is true that the meridians 

 selected are the coldest in some latitudes of the northern 

 hemisphere, inasmuch as they traverse the interior of the 

 continents, considerably near the eastern or colder side. The 

 longitude of 95'' W., for instance, passes nearly two degrees 

 west of Fort-Snelling, Iowa, which is very probably the coldest 

 meridian in the United States ; but as this same meridian 

 passes through the Gulf of Mexico, the result there at once 

 explodes the whole hypothesis. And as the same meridian 



