68 Dr. Holyoke's Estimate of the Excess of Ilcat and (httl 



mains a problem, whicli has never, I suppose, received a sat- 

 isfactory solution. 



Various conjectures have been formed upon the subject; 

 one or two of -which I will mention. The first, and per- 

 haps, the most commonly received opinion among ns, is, 

 "That those lakes and large tracts of inland waters, w^hich 

 lie back of pur settlements, being constantly frozen over every 



expose a large surface of ice to the air ; which b 



o 



hereby rendered very cold, and being soon w\afted to the sea-^ 

 coast,, where our mo>^ numerous settlements are situated, 

 occasions that degree of cold, which the inhabitants of 

 North America suffer beyond the Europeans in- the same 

 climate." To which I object, 1st. That the winds, which 

 for the most part produce our most intense cold, are not 

 westerly, as upon this hypothesis they ought to be, but 

 north westerly, or stiU more northerly^ winds, wdiich last 

 certainly do not blow over any great extent of water in 

 their passage to our coasts. 2d. The causp assigned does 

 not seem adequate to the effect ; for, though the lakes to the 

 westward of us are large, yet they bear but a small propor- 

 tion to the extent of land, over which the winds must pass, 

 ere they arrive at our settlements. 3d. I suppose that a 

 surface of frozen water does not render the air. fl.nf 



any degree colder, than an equal surilice of 



passes 



fr 



en earth; for frozen earth is as cold as frozen water; and 

 all the surface of the ground, between the lakes and us, is 

 frozen every winter, before the lakes themselves are. And, 

 J they do not render the air colder, after they are frozen, 

 tl-n an equal surflxce of frozen earth ; certainly it cannot 



be 



m 



