L06 



(.' O R D A N I> H EDUCTI X 



Taking the moan of the expressions for th" three stations, the following formulae 

 furnish the type-curve for hit. 74°.4 N., and long. 77°.0 W., for the (Humid and 

 annual variation of the atmospheric pressure: — 



Inches. 



7; = 29.823 + 0.012 am (0 + 346°) + 0.005 sin (20 + 171°) 

 B= 29.823 + 0.124 sin (0 + 348°) + 0.08S sin (20 + 221°) 



• 1 )'ut ni< d Extremes. 



The irregular oscillations from day to day are suhject to an annual variation, as 

 exhibited in the following table of average differences in the atmospheric pressure 

 on consecutive days. The daily changes were made out, irrespective of sign, and 

 were obtained from the comparison of the daily means of the aneroid readings. 



To the two localities — Baffin Bay and Port Kennedy, I have added, for com- 

 parison, Van Rensselaer Harbor, and also a column for a mean of the three 

 localities. 



In Baffin Bay the progression is more regular than at Port Kennedy; the mean 

 from the two stations compares very favorably with the result deduced from Dr. 

 Kane's observations. The oscillations in the winter months are twice as great as 

 those in the summer months. 



The larger variations in the atmospheric pressure have already been noticed in 

 the discussion of particular storms in the preceding part of the paper. 



Monthly and Annual Extremes. 



The following table contains the observed maxima and minima of the atmos- 

 pheric pressure in each month, as observed by or referred to the mercurial marine 

 barometer, i At 32° Fahr.) 



