266 Meteorological Observations. 



state, or while screwed up for safe transportation ; which are the 

 most common causes of error in the adjustment of the scale to its 

 proper height in barometers. Now as the mean annual pressure 

 at the two places, at the sea level, is presumed to be nearly equal, 

 we may add 0.376 inch, or three eighths of an inch, to all the 

 results in Mr. Templeman's summary, for the purpose of com- 

 parison with the observations at New York. 



With this assumed correction, we find that the mean height of 

 the barometer at St. Johns, at the sea level, for the five half years, 

 which include the months of November, December, January, 

 February, March, and April, which takes in the winter period, is 

 30.039 inches : while the mean of the five half years which in- 

 clude the remaining months, is 30.184 inches. The mean pres- 

 sure of the half year which includes the summer, we here per- 

 ceive, exceeds that which includes the winter, by the amount of 

 0.14-5 inches ; or one seventh of an inch, nearly. 



At New York, I find on the contrary, that the mean pressure 

 of the half year which includes summer, for the same period of 

 time, is less than that of the half year which inchides the win- 

 ter by 0.044 inch ; or something less than ^-^ of an inch : the 

 mean for the winter half years being 30.133, while that for the 

 summer period is 30.089, There appears no reason to doubt the 

 accuracy of these results, in either case. 



This analysis shows also an average difference of pressure at 

 the two places for the same half year ; assuming the same annual 

 mean : the inequality for the winter period being 0.094 inch, or 

 nearly one tenth of an inch greater at New York than at New- 

 foundland ; while for the half year that includes summer, which 

 exhibits the least fluctuations of pressure, and in which the equi- 

 librium of the atmosphere is least disturbed by violent winds, the 

 mean pressure is 0.095 inch greater at St. Johns than at New 

 York. 



It appears from the table, that the extreme range of the ba- 

 rometer at Newfoundland during the five years was 2.54 inches, 

 or two and a half inches, nearly : while at New York for the 

 same period, as corrected one fortieth for variation in the cistern, 

 it was 2.265 inches ; or tioo and a quarter inches, nearly. The 

 diff"erence of latitude in the two places is 6° 52'; the difl'erence 

 of longitude 21° 22'; both places being on the western margin 

 of the same ocean. 



