330 



Meteorological Observations at Montreal. 



The following are all the instances in which an inch of rain 

 has fallen in twenty four hours. 



Throughout the entire preceding discussion, I have carefully 

 distinguished the observations of different hours. The propriety 

 of this course has I trust been made sufficiently apparent. Ali 

 most every meteorological phenomenon has a diurnal inequality^ 

 Thus the heights of the barometer, thermometer and hygrome- 

 ter, direction and force of the wind, character and amount of the 

 clouds, as well as the amount of rain, change sensibly with th^ 

 hour of the day. I trust that heat will no longer be considerecl 

 as an unimportant agent in the modification of meteorological 

 phenomena ; and that hereafter, in publishing meteorological 

 means, the distinction of hours will not be disregarded. The 

 observer who publishes the mean of all his thermometrical ob-! 

 servations without regard to hours, not only cannot be sure oi 

 obtaining the mean temperature of his locality, but deprives oth-» 

 ers of the data necessary for determining it. 



I 



Art. YIT. — Meteorological Nummary of the Weather at Montreal^ 

 Province of Canada, in Lat. 45° 30' N., Lon. 73° 22' W.^ 

 {for five years, from 1836 to 1840, inclusive ;) iwm regis-* 

 ters kept by J. S. M'Cord, Associate Mem. Lond. Met. Soc.^ 

 Mem. Nat. Hist. Soc. Montreal, Cor. Mem. Lit. and Hist. Soc; 

 Q,uebec, and Albany Institute, New York. 



ANNUAL TEMPERATURE. 



Of this, 2.838 fell in thirty six hours. 



