82 Dr. Holyoke's Estimate of the Excess of Heat and Cold. 





tion reaches, the thermometer is never at its highest, at 

 such times, but commonly 6 or 8 degrees below it* 



Whence I think it may fairly be inferred (whether we 



h 



are able to account for it philosophically or not) that dry- 

 ness or dephlogistication; are in fact and nature, necessary to 

 the production of our intensest cold ; and probably of our 

 intensest heat. And if so, is it not natural to suppose, that 

 when the atmosphere of any country is usually both in sum- 

 mer and winter much dryer, and more dephlogisticated, than 

 another, that, ciBteris paribus, it should be Uotter in summer, 

 and colder in winter there, than in that other? 



But, allowing all that has hitherto been advanced npon 

 thil subject, I Avould not hastily conclude, that the" superiour 

 dryness and dephlogistication of our atmosphere is alone 

 sufficient to account for the whole of our superiour heat and 

 cold. There are probably other causes, which conspire with 

 it to produce^ the same effect. I shall mention one, which 

 I think of considerable moment. 



All 



* It majr perhaps, have tie appearance of paradox, to ascribe two such opposite ef- 

 fects, as heat and cold, to the same cause ; but this appearance will in a good measure 

 vauisb, if it should be found, as I suppose It may, that dcphloglstlcation produces cold, 

 by .ts chenucal effect upon tbe air: But that it produces heat only mcclaulcalhj, by 

 inducmg a more perfectly pellucid state of tbe atmosphere, whereby fewer of the sun's 

 rays are nUerceptod; and (a. dephlogisticated air Is specifically heavier by much, than 

 common at^ospherick air) by occasioning a greater weight and density of the air, near 

 the earth s surface, whereby the sun's iuiluence In producing heat is greatly Increased. 



liiGse considerations may serve to show wLt.- .»^m - i - , , i 



, , . , ^ ^ vc lo siicw, whj. cold IS so much more increased, by a de- 



pi og»„oate,l ,,.,.e of ,Lo aUnosphcre than leal. A„,l i, i, *.erval,lc, that .be difference 

 in irir ."'7°°"''"' ""» °f ''•'■-'' ■* «P0»1 to «,c sun's d,V.H rajs.and U,e other 

 gisticated state of the atmosphere, ° ' ^ 



f 



i 



