ABNORMAL VARIATIONS AT TORONTO. 115 



there is the general correspondence in the annual means exhibited in 

 table VII., exceptions in one month or another occur for each of the 

 other five points. 



BAROMETRIC PRESSURE. 



Table VIII. gives the mean abnormal variations of barometric 

 pressure for the diflPereiit years from 1854 to 1862 derived from six 

 daily observations. The greatest annual mean is 0.193, the least 170 

 and the general mean for the nine years 0.183. 



In table IX., designed to shew the monthly averages of the extent 

 of the barometric abnormal oscillations, the annual distribution re- 

 sembles in its general character that of the abnormal oscillations of 

 temperature. The quarterly averages are 0.191 in spring, 0.118 in 

 summer, 0.186 in autumn, and 0.231 in winter. 



The diurnal distribution of the abnormal variations of the barometer 

 are given in table X. In both series the most tranquil hour is 10 p.m. 

 and the most disturbed hour 8 a. m. An examination of the hourly 

 distribution in the separate months given by the earlier series, shewed 

 that 8 A.M. was the most disturbed hour in ten months out of the 

 twelve, the exceptions being February and December ; and that the 

 most tranquil hour was either 10 p.m= or midnight in every month but 

 November, when the minimum was at 4 p.m. 



Table XI. gives the mean abnormal variations of the barometer 

 that accompany different directions of the wind. 



According to the results furnished by the first seven years, the 

 highest barometer accompanies a wind from N. N. E., and the lowest 

 barometer one from S. W. In both series the barometer is above the 

 normal when the wind is from N., N.E., E., S.E., and S., and below 

 the normal when the wind is from S.W., W., and N.W. 



In table XII. are given the annual means of the changes without 

 regard to sign between the barometric pressures at like hours of con- 

 secutive days. 



In table XIII these differences are classified according to the 

 months. The correspondence in the two series is on the whole 

 tolerably close, the maximum occurring in either January or February 

 and the minimum in either July or August. Combining the two 

 series, and giving double weight to the first, the greatest monthly 

 average change in twenty-four hours is 0.281 in January, and the least 

 0.121 in July, the annual mean being 0.198. The quarterly means 



