11 



ANALYSIS OF THE OBSERVATORY RECORDS FOR AUGUST, 1864; 

 IN CONJCJNCTION WITH THOSE OF BIRTHS, DEATHS, kc. By 



E. SWABBRBCK HaLL. 



Most of the meteorological ]iheuoraena of the month were propitious to 

 health, auJ the long coatiuued excessive deaths have at length given way to a 

 mortality below the August average of the previous seven years. 



Atmospheric j)rcssure underwent frequent, sudden, and excessive fluctua- 

 tions, though the month's mean, 29854, is only + '071 more than the average 

 of the 20 years' standard. Tlie extremes of pressure were : — Maximum, 

 30*307 on the 7th, minimum, 29283 on the 17th; consequently the range of 

 the month was 1'024 inches. The extremes and the range were much greater 

 than this in 1863. The greatest movement of the barometer in any twenty-fovir 

 hours, was, — a rise of + ^(jQ of an inch on the 18th, preceded by a fall in the 

 previous twenty-four hours of — "538 of an inch. There was also the large rise 

 of + '592 of an inch on the 5th, and + '217 more on the following day, oa 

 which day the greatest number of deaths occurred (5) of any day in the month. 

 Altogether there weie movements exceeding one-fifth of an inch, on eleven 

 days of the month. 



Wind force had a total ©f 47'09 lbs. being -f l'241bs. more that the 

 average of the previous seven years, though but little more than half of what 

 August 1863 had. North, north-east, south-east, south-west, and north- 

 west, all prevailed more than usual, but the first and the last by much the 

 most so. South-west had the greatest excess above the average in force, then 

 north-west followed by west,and lastly east, by a few decimals; all the others 

 were below the average. The .directions, however, indicated by the vane in 

 Hobart city, by no means corresponded with those on Mount Nelson, 

 Fortescue Bay, and Low Heads. From other conditions of these winds, more- 

 over, it was certain that thej currents from the south-west generally prepon- 

 derated. The strongest winds recorded, 5-21 lbs., were noted three times, at 

 7 a.m. on the 5th, and at noon and sunset of the 15th. The calms wei'e 39, 

 which is -f 3 above the four years' average. 



Temperature, vmlike the preceding five months of the year, had a mean 

 below the 20 years' average by nearly half a degree ( — '48) being only 48 '22 

 degrees. In the previous nine years, only 1863 had a lower mean temperature, 

 t.e?, 47 '90 degrees. The mean temperature of the previous month (July) was 

 warmer by nearly one degree. The self-registering maxima and minima 

 thermometers for this month, gave a mean of 49 "61 degrees. The extremes of 

 temperature were unusually small for August ; the maximum was only 65 

 degrees on the 7th, and the minimum 34 degrees on the 26th. A lower 

 maximum (64) has only occurred once in the previous nine years fl857). Last 

 year had the same minimum ; but one degree higher maximum — 1861 had 

 also as high a minimum, but a maximum 7 degrees higher — 1859 had, too, a 

 minimum of 34, but with a maximum of 72 — all the rest of the nine years had 

 lower minima by one and two degrees. The extreme range of 31 degrees for 

 this mouth, is much below any of the pre\ious nine years, except 1857, which 

 had precisely the same. This equable cold temperature, combined with free 

 aerial movements, great atmospheric purity, and abundant moisture, was highly 

 conducive to health and life, as the mortuary tables show. 



The mean daily range of temperature was 16 '45 degrees, only differing 

 from the 20 years' average, by + '06 of a degree. At the same time it was 

 from half to six degrees less than any of the previous eight years. The greatest 

 range on any day, 28 degrees, took place on the 7th ; the smallest, 7 degrees, 

 occurred on the 23rd. 



Solar intensity mean 79 '40 degrees, was —2*37 below that of the previous 8 

 years. With so many cloudy and rainy days, such a result might be expected. 

 The maximum heat was 93 degrees on the 7th. Five out of the eight years had 

 higher maxima, the highest being 103 '5 in 1862. The minimum solar tempera- 

 ture was 60, and noted on the 3rd and 17th. 



Terrestrial radiation mean was, 37*53 degrees, being -f 1*05 above the mean 

 of the previous eight years. The maximum was 44 degrees on the 13th ; the 

 minimum was 30'50 on .the 26th, and higher than any of the previous eight 

 years had. 



Rain fell on 19 days, to the aggregate amoimt of 3*68 inches, the former 

 being -f 6'34 days above the average of the previous nine years, and the latter 

 -f 1*62 inches above the August mean of the 20 years' standard — only 1858, out 

 of the previous 23 years, had a greater amount of rain, t.«., 10*16 inches, but 

 that is also the maxiirum of all the months in all the years recorded. More- 



