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ANALYSIS OF THE OBSERVATORY RECORDS FOR 

 SEPTEMBER, 1866, IN CONJUNCTION WITH 

 THOSE OF BIRTHS, DEATHS, &c. By E. Swarbeeck 

 Hall. 



No September of the pre\'ious nine years was so favorable to health 

 and life as the present month. The deaths were less than in any former 

 September on record by 20 per cent, and below the average of the pre- 

 vious nine years by more than 33 per cent. Atmospheric pressure, though 

 constantly oscillating, had no extreme ranges ; wind movement was con- 

 stant, but moderate, and the quality of the air was most pure ; electricity 

 was abundant, and rain-fall sufficient. The month's mean was warmer 

 than the average, with extensive daily extremes, the latter being the only 

 phenomenon that apparently had any adverse efiFect upon health and life. 



Atmospheric pressure mean for the month was 29-730, being only + "048 

 above the mean of the 20 years' adopted standard. The maximum was 

 only 30-078, recorded on the 23rd. This is the lowest maximum that 

 has been registered since 1856. The minimum was 29-240, recorded on 

 the 15th. In only nine, out of the previous 25 years, was a higher 

 minimum noted. The range of the month -838, is the smallest that has 

 been registered since 1859. On twelve days in the month the barometer 

 varied one-fifth of an inch, but the greatest movement on any day was 

 only -418 of an inch, recorded on the 9th. This is the smallest day range 

 for any day in September of the previous ten years. When compared 

 with the corresponding data in September, 1865, it is evident how much 

 more favorable to health and life was the present month as regards atmos- 

 pheric pressure. 



Wind-force'h.2idiSiioidloi 80-15 lbs., which is +31-52 lbs. more than 

 1865 had, and + 7*62 lbs. more than the average of the pre^dous nine 

 years. Nevertheless, there were no storms, the greatest pressure to the 

 square foot having been 5-21 lbs., and that only recorded seven times 

 out of the 90 observations recorded. The calms, 17, were — 7-12 below 

 the average of the previous eight years. Constant, but moderate, move- 

 ment was therefore the rule. South-west, west, and north-west winds 

 were alone more numerous than usual, the first and last being also 

 greatly above the average in force, and the west very little below it. 



Temperature mean, 52-23 degrees, was + 1-31 above the 20 years' average, 

 though somewhat cooler than 1865 was, i.e., — -09 of a degree. By the self- 

 registering maxima and minima thermometers, the mean was only 51-28 

 degrees. This is the third month in succession in which this remarkably 

 unusual occurrence of a lower mean by these thermometers, than by the 

 three daily observed ones has been noted. The maximum, 75 degrees, 

 was registered on the 1st ; the minimiun, 34, on the 13th and 30th. ^ The 

 month's range was consequently 41 degrees, which is greater than in any 

 September since 1857. The mean of all the maxima, or high-day tem- 

 peratures, was 61-47 degrees,being — 1*80 degrees less than last year. The 

 minima or low-night mean was 41-10 degrees, being — 2-53 degrees less 

 than in 1865. 



The daily -range of temperature had a mean of 20-37 degrees, being 

 + 2-35 above the 20 years' average, and + -74 of a degree higher than 

 1865 had. The greatest range on any day was 31 degrees, recorded on the 

 23rd. This is the highest noted since 1856 _; that year, 1855, and 1841, 

 only, having a higher range than the previous 25 years. The effects of 

 these wide daily-ranges accompanied with a large amoimt of ozone, was 

 to cause inflammatory affections of the respiratory organs, from which 

 diseases seven deaths were registered,being one fourth of the whole month's 

 mortality. Not one of the deaths, however, were imder 28 years of age, 

 and three of them were aged 63, 69, and 80 years respectirely. 



