A T M S r U E R I C PRESSURE. 



219 



Mean Atmofi_i)7t,erlc Pressure at the Level of the Sea. 



We obtained the annual average value of the atmospheric pressure = 29"'.82J: ; 

 the reduction to the sea level is +0"'.006, hence the height of the barometer at the 

 sea level in latitude 78° 18' ^ 29.830 inches. 



At Van Rensselaer Harbor in latitude 78 37 29.775 



" Port Kennedy " " 72 01 29.938 " 



" Baffin Bay " " 72 30 29.755 " 



Average, 751 29.821 " 



MontJili/ and Annual Extremes of Pressure. 



The following table contains the observed maxima and minima of atmospheric 

 pressure in each month ; attached thermometer at 32°. The corresponding range at 

 Van Rensselaer Harbor has been added for comparison. 





Maximum. 



Minimum. 



Port Foulke 

 range. 



Van Rensselaer Ear. 

 range. 



Septeaiber .... 



30'M3 



29^2'? 



0-°.86 



I'Ml 



October . 











30.22 



28.94 



1.28 



1.28 



November 











30.Y4 



29.59 



1.15 



1.30 



December 











30.n 



29.17 



1.54 



1.48 



January . 











30.4.5 



29.14 



1.31 



1.36 



February- 











30.20 



28.98 



1.22 



1.61 



March 











30.53 



29.23 



1.30 



1.31 



April 











30.61 



29.44 



1.17 



1.09 



May 











30.58 



29.50 



1.08 



1.30 



June 











30.01 



29.31 



0.70 



0.78 



July 











30.11 



29.27 



0.84 



0.57 



August . 















- - - - 



0.85' 



0.83 



Mean ..... 







1.11 



1.17 



' Interpolated. 



The monthly range is greatest in winter and least in summer. 

 Observed absolute maximum and minimum and extreme range, referred to 32° 

 Fah., and at the level of the sea: — 



Maximum 30'^74 November 25, 1860 



Minimum 28.93 October 16, 1860 



Range ...... 1.81 



The extreme range at Van Rensselaer Harbor was 2.13 inches. 



Relation of the Atmosplieric Pressure to the Direction of the Wind. 

 The changes of the barometric pressure, depending upon the direction of the 

 wind, can only be investigated approximately from our observations, since the wind 

 appears to blow principally from two directions, the number of entries from other 

 directions being exceedingly few ; besides, the series of barometric observations does 

 not extend to a full year, and the daily observing hours are not symmetrically dis- 

 tributed over the twenty hours. By means of the preceding formida expressing 



