no 



MEAN METEOROLOGICAL RESULTS 

 BAROMETER. 



1 1864. 



^Average 



of 

 18 years. 



Extrerces. 



Mean pressure of the year 



Month of highest mean pressure 

 Highest mean monthly pressure 

 Month of lowest mean pressure 

 Lowest mean monthly pressure 



Date of highest pressure in the year \ 



Highest pressure 



Date of lowest pressure in the year | 



Lowest pressure 



Range of the year 



29.5596 



June. 



29.6545 

 May. 

 29.4721 



Dec. 9, 1 

 10 a.m, / 



30.327 

 Nov. 4, ) 

 2 p.m. i 



28.671 

 1.656 



29.6133 



Septemb'r 

 29.6629 

 June. 

 29.5624 



Average 



of 

 9 years. 



30.372 



28.692 

 1.780 



J 29.6679 in 

 I 1849. 

 June, 1849. 



29.8030 

 March, 1859. 



29.4215 



Jan. 1855, 



30.552 



March, 1859. 



28.286 

 J 2.106 

 I in 1859. 



29.5596 ia 



1864. 

 June, 1864.^ 



29.65^ 

 Nov. 1849.. 



29.5S6S 



Dec, 185*- 



S0.245 



March^lS^ 



28.8^ 



1.429 



in ISeO. 



RELATIVE HUMIDITY. 



1864. 



Average 



of 

 20 years. 



Extremes. 



Mean humidity of the year 



Month of greatest humidity < 



Greatest mean monthly humidity 



Month of least humidity , 



Least mean monthly humidity , 



76 

 Dec., Jan. 

 and Feb. 



82 

 June. 



63 



78 



Jan. 



83 

 May. 



72 



82 in 1851. 

 Jan. 1857. 



Feb. 1843. 



58 



73 in 185&, 



Dee. 385f^ 



81 



April, 184a. 



76 



EXTENT OF SKY CLOUDED. 



1864. 



Average 



of 

 12 years. 



Extremes. 



Mean cloudiness of the year 



Most cloudy month 



Greatest monthly mean of cloudiness 



Least cloudy month , 



Lowest monthly mean of cloudiness . 



0.65 

 December 

 0.80 

 June. 

 0.30 



0.60 

 December 



0.75 

 August. 



•0.47 



0.65 

 0.83 

 0.30 



0.57 



0.7S 



*0.45 



* The average lowest monthly mean of cloudiness in column (2) is the least of the th© 

 twelve monthly means derived each from twelve years, and does not include the lowest 

 months in each year, as these fall diiferently in different years. This explains why the- 

 highest minimum in column (4) should be less than the average minimum. The average 

 value of the greatest as well as of the least monthly means of the several elements, and 

 given in column (2), are similarly obtained, and therefore do not necessarily lie between the 

 numbers in columns (3) and (4). 



In the case of the warmest days, or the highest temperatures in each year, and other 

 analogous quantities, the averages in column (2) are derived from the corresponding valnea 

 in each year, independently of the time of their occurrence, and must of necessity lie be- 

 tween the numbers in columns (3) and (4.) 



