27 



ANALYSIS OF THE OBSERVATORY RECORDS FOR MARCH, 

 1865, IN CONJUNCTION WITH THOSE OF BIRTHS, DEATHS, 

 &c. By E. Swaebeeck Hall. 



Thia March has been much more favorable to life than last year's, though 

 fiingularly enough the total mortality is almost exactly that of the mean of the 

 Ijrevious eight years. The diseases, however, which caused death were princi- 

 pally those of long standing, rendered fatal by sudden variations of the 

 temperature and pressure of the atmosphere. The class depending mainly 

 upon purity of the air, (zymotic) contributed far less than the usual average to 

 the mortuary records. 



Atmospheric pressure mean 29 "874, differed little from the 20 years' adopted 

 standard average, being only + "017 of a degree higher. The contrast, however, 

 with the high mean of March last year, 30 '109, is noteworthy in connection 

 with its much heavier mortality. The extremes of the present month were, 

 minimum 29-330, on the 11th ; maximum 30-207, on the 28th. The range -877, 

 though somewhat less than that of March 1864, was greater than that of the 

 three preceding years. The daily perturbations were more numerous and wider 

 in extent, than last year, there having been nine days on which the movements 

 of the barometer exceeded one-fifth of any inch. The greatest range for any 

 day was a fall of — "376 of an inch on the 13th. The most extensive rises were 

 on the 6th and 11th, +'359 + '355 respectively, the latter having the greatest 

 number of deaths of any day in the month. 



Windfo7'ce had a total of 57*51 lbs. being +4 '97 more than the March 

 average of the previous eight years, and nearly the same excess over March, 

 1864. Nevertheless, the predominant winds in force and number. North, 

 and North West, were those least favorable to health. The number of faint 

 South winds was unusual, 12 in excess, yet not reaching the average in 

 strength ; South-East, South -West, and West were all below the mean in both 

 frequency; force the greatest pressure to the square foot, 5.21 lbs, was noted 

 five times i.e. on the 5th, 15th, twice on the 16th and the 18th, one West, two 

 each North and North-West. No hot winds occurred. 



The mean temperature of the month was colder than that of any March 

 since 1854, being only 59.02 degrees; which is— 00.96 less than the 20 years* 

 average. March 1864 was somewhat above the 20 years' mean, thus afford- 

 ing another datum to account for the superior health of the present month. 

 The mean deduced from the self -registering thermometer is, 60-90 degrees, 

 giving a rather wider discrepancy than usually occurs, and very different to 

 what was remarked for February. The warmest day of the month, the 4th, 

 had the maximum of 82 degrees ; and the coldest night in the month was 

 that of the 31st when the self -registering thermometer fell to 41 degrees. 

 Last year the extremes were 81 and 43 respectively. Sixteen times in the 

 previous 24 years has the maximum much exceeded that of the present year, 

 four times being above 90 and the highest 99 degrees in March 1861. Seven 

 times in the same period has the minimum fallen lower, the lowest being 36 

 degrees in March 1850. The mean of all the maxima exceeded both February 

 and January, being 71.19 degrees ; but the minima mean, on the other hand, 

 fell below both those months, being 50-61. 



The daily-range of ^em^jem^iire mean, was, 20-58 degrees ; which is -f'54 

 of a degree more than the 20 years' average, and even + "26 higher than in 

 last March. The gi'eatest range of any day was 33 degrees, noted on the 4th, 

 and the 28th. March 1864 had four degiees less, and the two previous years 

 •were not so variable as the present one. The smallest vai-iation was only 6 

 degi-ees recorded on the 14th. In 1864 the minimum was 13 degrees. 



The Solar-thermometer mean was, 100-87 degi-ees, being — 2-68 below the 

 mean of the previous nine years, and —7 '00 less than March 1864 had. The 

 much greater number of wet and cloudy days in the present month accounts 

 for this. The greatest heat was 120 degrees on the 4th. Last years' maximum 

 was four degrees more, and the thermometer only marked below 100 degrees 

 six times ; while in the present month it has done so fourteen times. 



The Terrestrial radiation thermometer had a mean of, 46-93 degrees, which 

 is — 1*36 less than the average of the previous nine years, and — '57 less than 

 1864 had. It would appear from this, that though the day time was so much 

 more cloudy in the present March than in that of 1864, yet that in the night 



