81 



ANALYSIS OF THE OBSERVATORY RECORDS FOR AUGUST, 1865, 

 IN CONJUNCTION WITH THOSE OF BIRTHS, DEATHS, &C. Bt 



E. SWARBRECK HaLL. 



This month was characterised by mild, dry, sunny, and agreeable weather, 

 with enough of wind movement and electricity to produce a high state of aerial 

 purity, and consequently the community at large enjoyed a better state of 

 health than is usual in August, and the deaths were below the avei'age of the 

 previous eight years. Children, and adults up to 50 years of age, furnished 

 an unusually small proportion of the deaths ; more than two-thirds of the 

 total mortality' being from 50 to 85 years old. 



Atmospheric 2}ressure mean, 29 "919 is +"136 above the 20 years' adopted 

 standard, and also higher than that of either 1864 or 1863. The maximum of 

 the month was registered at 7 a.m., of the 8th, being 30*566. This was the 

 most fatal day to life in the month. The minimum, 29*245, was recorded on 

 the 27th. In the previous 24 years, only August 1860 had a greater maxi- 

 mum, but the minimum was frequently much lower. The extreme range, 1'32I 

 inches, was considerably greater than August 1864 had, though less than that 

 of 1863. The greatest movement of the barometer in any 24 hours from 1 

 p.m., to 1 p.m., was a fall of — '564 of an inch on the 26th, and its influence is 

 marked in the mortuary records : — Two persons above 70 years of age, and 

 another nearly 40 —long suffering from heart-disease — , succumbed to it. On 

 fourteen days of the month, the barometrical movements exceeded one-fifth 

 of an inch. It is remarkable, that of the 33 observations recorded on the 

 first eleven days of the month, the atmospheric pressure was only once below 

 30,0JO inches and so steadily was this high pressure maintamed that only on 

 the 11th did the perturbation in the 24 hours rise to one-fifth of an inch. The 

 daily movements, therefore, in the remaining 20 days of the month were 

 unusually numerous and extensive. This condition of atmospheric pressure 

 told heavily on aged and enfeebled persons, and produced a remarkably 

 abnormal proportion of deaths of persons above 60 years of age, but was 

 innocuous to those of all ages below. 



Wind-force in the aggregate, amounted to 40'301bs., being + !l*941bs., above 

 the 4 years' average given in the standard tables, but — 5*71 below the average 

 of the last eight years, — the three last years very windy Augusts, having raised 

 the average very considerably. The calms, 36, were exactly the four years' 

 average, — but -1- 1 "57 above the mean of the last seven years. The highest 

 wind-force registered was only 2"601bs., pressure to the square foot, and was 

 recorded eight times. So much moderate wind-movement, so equally dis- 

 tributed, is not usual in August, for the records hitherto, exhibited either 

 very little aerial movement, or very boisterous ones. The prevailing winds 

 wei-e, south-ioest, ^oest and north-ivest, all of which exceeded the mean both 

 in frequency and force. From the other five points of the compass, the winds 

 were all below the average in frequency, and with the exception of north-east y 

 also less than the mean in force. 



Temperature mean, 49 "31 degrees, is + 00*61 above the 20 years' average, but 

 much warmer still than 1864 and 1863 were. The mean of the self -registering 

 maxima and minima thermometers, was 50*03 degrees, being an unusually 

 small difference between the two sets of instruments. The extremes of tem- 

 perature this month were, 66 degrees recorded four times, and 32 registered for 

 the nights of the 15th and 25th. The range was somewhat less in the August 

 of the two previous years, but the extremes for August in the last 24 years 

 were, 82 maximum in 1862, and minimu-n of 30*20 in 1846. The meanof all 

 the maxima for the present month is, 60'48 degrees, while that of 1864 was 

 only 57*84 degrees. The mean of all the minima for this August is only 

 39 58 degrees, while that of last year, was 41*38. So that the August of 1865 

 had warmer days and colder nights than the August of 1864. Eminent Sani- 

 tarians have compiled tables showing the hour at which death takes place, 

 and it is found that the deaths are by far most numerous in the coldest hours 

 of the night. I have no doubt the mortuary records of the present month 

 would show this very clearly had I the means of ascertaining the details. 



Daily range of Temperatarc mean was, 20*90 degrees, being, -j-4'51 degrees 

 higher than the 20 years' mean, and nearly the same above 1864 and 1863. 

 Only in August 1861, and 1862, did the mean daily-range of temperature exceed 



