Heterology of the year 1861. 41 



The greatest intensity of the SurCs rays was 104^3 degrees, 

 which is less by 6^3 degrees than the intensity for the year 

 1860, and is 12°Y degrees less than the intensity for the year 

 1859. The lowest point of the terrestrial radiation^ was — 39°4 

 degrees (below zero.) 



Dew. — The yearly amount of dew was below the usual mean 

 or average ; an apparatus has been used for a short time for the 

 purpose of ascertaining the hour at which dew begins to fall and 

 when it ends, and also the amount, and it is believed will lead to 

 some interesting results in this department of research ; the appa- 

 ratus is self-registering and leaves a permanent impression. 



Wind. — The most prevalent wind during the year was the N. E. 

 by E. and the least so E. by N. ; the next in frequency was the W. 

 and W. S. W. and a good deal of S. E. winds prevailed ; below is 

 a table of the amount of horizontal miles of wind for each month : 



giving a total for the year of 55296.78 miles linear, which is 

 11083.26 miles more than the amount for the year 1860 ; the 

 mean velocity for the year was 6.312 miles per hour, which shows 

 an increased velocity of 1.270 miles per hour for 1861 over that 

 of 1860. June was the calmest month last year and indicated only 

 2905 . 36 miles ; a tornado passed over Montreal on the 9th of July, 

 but was little felt here ; on the 10th of August a very heavy hail 

 storm passed near this place over St. Laurent and Montreal, doing 

 considerable damage to crops and buildings; there were several 

 storms of wind during the year preceded by rain and a low 

 barometer. 



The Aurora Borealis, was visible at observation hour on 42 

 nights ; a bright display with considerable magnetic disturbance 

 occurred on the night of the 1st of September, the same period 

 that the splendid display which caused so much sensation over 

 the world occurred last year. 



The Zodiacal Light was frequently seen ; it was generally bright 

 and well defined. 



Solar and Lunar Halos have been more than usually frequent 

 during the year. A remarkable solar halo occurred on the 12th 

 of August, when the temperature had fallen considerably during 



