THE METEOROLOGY OF EDINBURGH. 



685 



Looking at the smoothed means in Table II. it will be seen that pressure is above 

 the annual average on 195 days and below it on 169 days. The most pronounced 

 maximum occurs from April 7 to July 3, during which time pressure is below the 

 mean on only one day, viz., May 18. The period of low pressure is from September 

 26 to February 11, but anti-cyclones occur from time to time, the longest spell of 

 uninterrupted low pressure being from October 6 to November 6. The unsteadi- 

 ness of the barometer is remarkable, considering that a period of fifty years is under 

 discussion, there being no less than twenty-seven well-defined troughs and a similar 

 number of crests in the air waves, the mean height of the barometer during these being 

 29*808 inches and 29*909 inches respectively. The cyclonic and anti-cyclonic periods 

 will be examined in detail when the climatic features which accompany them are 

 under discussion, but attention may be here called to the remarkable barometric 

 depression in November which is the most noteworthy feature of the pressure curve. 

 The mean barometric pressure on November 18 for the period under review is 29*902 

 inches, after which it falls slowly to 29*831 inches on the 21st. Pressure then 

 diminishes with great rapidity, and with one or two minor oscillations falls to the 

 minimum on November 26, when the low value of 29*628 inches is attained. A 

 rapid rise then sets in, which culminates on December 2 in a reading of 29*922 

 inches. The following table shows the mean pressure for each day of the period 

 November 18 to December 2 on the average of fifty years, as well as mean values for 

 Edinburgh and Greenwich for the thirty-three years 1861-93. The Greenwich values 

 were extracted from the detailed annual volumes of The Greenwich Magnetical and 

 Meteorological Observations, and are the mean of twenty-four hourly observations, 

 while the Edinburgh readings were made at 8 or 9 a.m. 



Date. 



Edinburgh, 50 Years. 

 At 32° and Sea-Level. 



Edinburgh, 33 Years. 

 At 32° and Sea-Level. 



Greenwich, 33 Years. 

 At 32° and Sea-Level. 



Inches. 



Inches. 



Inches. 



November 18 

 19 

 20 

 21 



;) - ,J - 



22 

 23 

 24 

 25 

 26 

 27 

 28 

 29 

 30 

 December 1 







29-902 

 •842 

 •841 

 •831 

 •655 

 •695 

 •716 

 •637 

 •628 

 •706 

 •759 

 •734 

 •791 

 •836 

 •922 



29-937 



•888 

 •930 

 •893 

 •677 

 •718 

 •735 

 •619 

 •605 

 •667 

 •772 

 •764 

 •774 

 •821 

 •935 



30023 

 •004 

 •023 



29-975 



•851 

 •859 

 •857 

 •774 

 ■778 

 •850 

 •915 

 •884 

 •884 

 •912 

 30-004 



Hence the returns from the two places are substantially the same, the barometer 



