METEOROLOGY. 163 



ence to the different hours of the day, 2 p. m. and midnight ■were the hour3 at 

 ■which the extent of sky clouded was greatest and least. 



Wind. — The resultant direction of the wind for the year was considerably more 

 from the west, and the resultant velocity as well as the mean velocity was much 

 less than in the preceding three years. The most windy p'-onth was April, with a 

 mean velocity 9.51 miles per hour, and the least windy month was June, with a 

 mean velocity 5.33. The most windy day was 21st March, with a mean velocity 

 of 23.62 miles, and the most windy hour absolutely was from 8 to 4 p, m. on the 

 same day, when the velocity was 35.4 miles. The most windy hour on the average 

 of the year was from 2 p. m. to 3 p. m., with a mean velocity of 10.51 miles, and 

 the least windy honr from midnight to 1 a. m., with a mean velocity of 5.88 miles, 

 Eain and Snow. — The depth of rain, 28.031 inches was 2.674 inches below the 

 average, and the depth of snow 45.4 inches or 16-2 less than the average. The 

 total depth of rain and melted snow thus fell short of the average by nearly 4.3 

 inches. 



May was the most rainy month, estimated by the quantity of rain that fell, but 

 considered with reference to the number of rainy days, October and May were 

 equally rainy. February was in both respects the least rainy month. The most 

 rainy day was May 11, when the depth of rain was 1.590 inches, and the days 

 on which the heaviest fall of snow occurred were February 1 and 13, on each of 

 which days it fell io the depth of 6 inches. 



The fall of rain was distributed over 131 days, and the fall of snow over 67 

 days, including some days enumerated as days of rain ; and there were 178 days 

 without either rain or snow. The rain occupied about 684 hours, and the snow 

 about 277 hours in its fall, giving thus a total of 861 hours, or nearly 36 days, or 

 nearly one-tenth of the year when either rain or snow was actually falling. 



The hour when rain was most frequent through the year was 1 p. m. to 2 p, ra., 

 the hours at which snow was most frequent were from 10 a. m. to 11 a. m., and 

 from 1 p. m. to 2 p. m. ; and the hour most subject either to rain or snow was 

 from 1 p. m. to 2 p. m. 



The hours most free from rain and snow considered separately, were from 10 

 a., m. to 11 a. m„ and from 6 p. m. to 7 p m. for rain, and from midnight to 1 

 a. m. for snow ; and the hour most free from rain and snow taken collectively was 

 from midnight to 1 a. m. 



Thunderstorms. — There were but 19 thunderstorms, reckoning as such those 

 cases in which thunder or lightning occurred accompanied by rain or hail ; but 

 there were besides 31 instances in which thunder and lightning occurred separately 

 or together, but unaccompanied by either rain or hail. 



Auroras, — Auroras were more frequent than during the preceding five years, 

 and that of Oct. 27 exceeded in brilliancy any that were observed within that 

 period. 



FrOm the foregoing statements, as well as from the accompanying table, it would 

 appear that 1858 may on the whole be characterized as a moderate and average 

 year, the most marked exception being the early date of the maximum of summer 

 heat, the somewhat scanty supply of rain and snow, taking one month with the 

 -other, and its unusually large amount in the month of May. 



G. T. K. 



