OF THE OBSERVATIONS FOR ATMOSPHERIC PRESSURE. 103 



Diurnal variation of the atmospheric pressure during the year from September, 

 1858, to August, 1859, at Port Kennedy, in latitude 72°. N., and longitude 94°.2 

 W. 29 inches is to be added to the tabular numbers, which, as well as the pre- 

 ceding tabular numbers for 1S57-8, should be considered as reduced to the tem- 

 perature 32° (Fahr.). 



These results, when expressed analytically by means of Bessel's form of periodic 

 functions with application of the method of least squares, become — 



1. For Baffin Bay, 1857-1858— 



Inches. 



b = 29.743 + 0.013 sin (6 + 5 C ) + 0.004 sin (20 + 159°) 



2. For Port Kennedy, 1858-1859— 



Inches. 



b = 29.925 + 0.021 sin (0 + 22°) + 0.009 sin (20 + 150°) 



3. For Van Rensselaer Harbor, 1853-54-55, for comparison— 



Inches. 



b = 29.765 + 0.003 sin (0 + 290°) + 0.002 sin (20 + 204°) 

 In which expressions the angle 6 counts from noon at the rate of 15° an hour. 



The comparison of the observations with the values deduced by the formulas is 

 shown in the following two diagrams, in which the observed values are indicated 

 by dots. 



Diphmal Variation op Atmospheric Pressure in Baffin Bay. 

 Latitude 72°. 5 N. 



