9 



ANALYSIS OF THE OBSERVATORY RECORDS FOR FEBRUA.RY, 

 1865, IN CONJUNCTION WITH THOSE OF BIRTHS, DEATHS, 

 &o. By E. Swarbreck Hall. 



Though some of the meteorological phenomena this month were inimical to 

 health and life, yet others were so propitious, that the general result was favor- 

 able, and the mortuary record is,therefore, considerably below the 8 yrs.' average. 



Atmosjiheric jjrcssure hud the widest rsiUgGthiH mouth, I'lQd inches, of any 

 February in the previous 24 years, except February 1846, when it was 1'270 

 inches. The extremes were only eight days apart, the minimum, 29 '099, being 

 noted On the Srd, and the maximum, 30 •295, on the 11th. The greatest move- 

 ment on any day was a fall of — "584 of an inch on the Srd ; and the greatest 

 rise was + *532 on the 8th : other fluctuations, exceeding one-fifth of an inch, 

 occurred eight times. Though the daily valuations of pressure were so inces- 

 sant, yet the mouth's mean, 29'80l, only differs from that of the 20 years, by 

 being — '049 below it. As usual this perturbed state of atmospheric pressure 

 had a very fatal effect on aged and diseased persons. 



Wind-force total for the month, was only 44"21 lbs., 14*40 less than the 

 average of the previous eight years. The calms were 19, being + 12-7 more 

 than the mean of the seven years preceding. North-west winds were more 

 than usually prevalent, but of so gentle a character tliat the force was consider- 

 ably below the average. On the other hand, north winds were fewer in 

 number, but stronger in force than usual. South-east, the most auspicious 

 wind for health, was greatly below the mean, both in frequency and force. In 

 some measure this was compensated for by south-west and west winds being 

 above the average, botli in freqiieucv and force. The strongest wind of the 

 month had 5'21 lbs. pressure to the square foot, but was only recorded once, 

 i.e., at 7 a.m. on the 4th, the direction being from the south, west. 



Temx)erature by three daily observations had a mean of GO "74 degrees, which 

 is 1 '79 degrees less than the 20 years' average for February, though only 

 differing fro.Ti February last year, by -f* 37 of a degree It is remarkable that 

 the mean for the self -registering maxima and minima thermometers, was below 

 the foregoing, being only 60 'Gl degrees. Never before has such a disparity 

 been recorded, the usual fact being an excess of about one degree for the mean 

 of the self -registering, over that of the observed thermometers. The maximum 

 temperature of the month was only 79 degrees on the 22nd, which is the lowest 

 maximum for February in the last 24 years, with the exception of 1853, when 

 it was only 77*80. The highest ever recorded in this month was 100 degrees, 

 in 1847. Thirteen other years have had maxima between 90 and 100 degrees. 

 The minimum of the present month was 43 degrees on the 8th, which is not 

 remarkable. The month's range, therefore, was only 36 degrees ; 1861 had one 

 degi'ee less,but all the other 9 of the previous 10 yrs. , ranged from 43 to 53 degi-ees. 



Daily ramje of temperature had a mean 1*89 degrees below that of the 20 

 years, being only 18 '50 degrees, and varying from that of February 1864, by 

 only + '30 of a degree more. The greatest range was 27 degi'ees on thel2th, 

 and the smallest, 12 degrees, on the Srd. Except in 1861, when the maximum 

 range was one degi-ee less, no other year since 1853 had so small a maximum. 

 The highest was 51 degrees in February 1856. So equably cool a temperature 

 for this usually hot svxmmer month, numerically the most fatal to life of any 

 month of the twelve, though having the smallest number of days, was most 

 propitious to health and life. 



The Solar Thermometer had a mean of 100*55 degrees, being — 1-47 degrees 

 less than the average of the previous 9 years, and — 1*58 less than last year. 

 The maximum record was on the 12th. being 122 degiees. Last years was higher 

 by seven degrees ; and out of theprevious ten years, seven others greatly 

 exceeded that of the present month ; 1857 having the maximum, — 143 degrees. 

 The minimum record of the present month was 78 on the Srd. 



Terrestrial radiation mean, was 48 "28 degrees, being— 1*33 below the avei-tige 

 of the previous nine years, and — '82 less than 1864 had. With such a number 

 of wet days, and so high a cloud mean, so low a mean for this thermometer is 

 very unusual, and indicates clear nights. The extremes were, 39 degrees on the 

 8th, 58 degrees on the 15th. 



Baiti fell to the aggregate amount of, 2*94 inches, being exactly double 

 the February average of 20 years. 15 days were recorded wet, being twice as 

 many as the average of the previous ten years. On the 3rd, 6th, 16th, 17th, 27th, 

 28th, it was copious enough to flush the surface drains. At daylight on the 



