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ANALYSIS OF THE OBSERVATORY RECORDS FOR 

 DECEMBER, 1866, IN CONJUNCTION WITH 

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

 Hall. 



While December, 1865, had the smallest mortality for any December of the 

 last ten years, the present month's deaths were more numerous than any, except 

 ]8fi2 and 1859, and exceeded last yeai''s by upwards of 66 per cent,, and the 

 averao;e of the previous nine years by about 15 per cent. In the analysis of 

 the different meteorological phenomena of the present month, contrasted with 

 December, 1865, it will be seen, that atmospheric pressure, wind movement and 

 its purity, heat of the sun, elastic force of vapour, were all less favorable to 

 health than in 1865. The weather generally, however, was both pleasant to 

 the feelings, and conducive to vegetation. 



Atmospheric pressure had the very high mean of 29'915 inches, being + '145 

 above the 20 years' standard mean, and + •253 higher than December, 3865, 

 had. Only December, 1855, out of the previous 25 years, had a greater mean 

 pressure. The maximum, 30 '297, occurred on the 4tli, and the minimum, 

 29 394, was recorded on the 26th. Only 1855 had a higher maximum, and 

 only 1862 and 1847 had higher minima. The extreme range of pressure for 

 the month was only '903 of an inch, and has often been exceeded ; December, 

 1865, had a ran?e greater by + "180. The greatest movement in the mercurial 

 column was a fall of - - '408 of an inch on the 23rd, followed by a rise next 

 day of + '288. There were six other days on which the movement exceeded 

 one-fifth of an inch. Continuous high pressure, with moderate deviations 

 therefrom, either by rises or falls of the barometer, characterised this month. 



Wind-pressure total was 80'121bs., which is — 7'301bs. less than the average 

 of the previous nine years. South-east winds were the most numerous, but 

 north-icest had the greatest force. Though 1835 had a less total force than the 

 present year, yet winds from south-east, south, south-ioest, u-est, the healthiest 

 winds that blow, were about one-fourth more forcible than in the present 

 December. The strongest winds recorded had 5'211bs. pressure to the square 

 foot, and were registered four times. There was a hot wind on the 23rd, but 

 not of a very strong or oppressive character. There were only 9 calms, being 

 — 4*25 less than the average of the previous eight years. 



Temperature mean, 6 ''87 degrees, was — 1*20 below the 20 years' average, 

 though + 1'46 above December, 1865. The self -registering maxima and 

 minima thermometers gave a mean below the observed ones, (as they have done 

 consecutively since June last) i.e., only 59 05 degrees. The mean of all the 

 maxima or liigh-day temperatures was 6913 degrees, being one degree less than 

 last year. The minima or low-night temperatures had a mean of 49 00 degrees, 

 whichis —0015 less than 1^65 had. The highest temperature recorded was 80 

 degrees in the afternoon of the 23rd and 30th, and the lowest was 40 degrees of 

 the night of the 7th. The mean of the wet-bulb self -registering thermometer 

 was .54 00 degrees. 



Daily-raniicoi temperature had a mean of 20-16 degrees, being —'39 less 

 than the 20 years' average, and —'20 less than 1865 had. The greatest range 

 of any daj was 31 degrees on the 13th, and the smallest 9 degrees on the 16th. 

 Though the present month was warmer on the whole, and had a smaller daily 

 variation of temperature, and less ozone, yet inflammatory affections of the 

 respiratory organs were more pre vale it than in 1865, and caused four deaths, 

 all young children, while 1865 had not any. 



Solar-Lttensifi/ menn, 105 03 degrees, was + 1' 06 above the average of the 

 previous 10 years, and -f 2 74 more than 1865 had. The extremes were 117 

 degrees on the 9th, and 60 degrees on the 16th. Last year they were res- 

 pectively, 1 1 9 and 58. 



Terrestrial- Radiation had a mean of 46-94 degrees, which is_^— 1'30 less 

 than the average of the previous ten years, and — '76 less than 1865 had. No 

 year of the previous ten, except 1858, had so low a mean of this instrument. 

 The maximum was 56 degrees in the night of the 29th, the minimum 37 '5 on 



