298 REPORT=~1852. 
The Tables III., V., VI. exhibit the mean range of the self-registering 
thermometer through the several years, months and seasons, with the differ- 
ences from the seasonal and annual means. The mean annual range of 
temperature is 64°°25, and the mean monthly range 32°51 ; while the greatest 
monthly range, that of April, is 6°49 in excess, and the least monthly ranges, 
namely, those of November and December, are severally 4°95 in defect 
from the general mean. 
- In Table VII. is given the number of days on which the self-registering 
thermometer was at or below 32°; the average yearly number being 53. 
2. Barometric pressure (Tables VIII., IX., X., XI.).—The instrument 
employed was a standard barometer of Newman’s construction, of *546 in. 
bore, with moveable brass scale, and which had been compared with the 
flint-glass barometer at the Royal Society’s rooms. The cistern was 18 feet 
above the ground, and about 44:7 feet above the mean level of the sea. 
The Tables VIIT., [X., X. exhibit the mean monthly and annual barometric 
pressure, deduced from observations at 9 A.M. and 3 p.M., corrected for tem- 
perature, with its distribution through the several meteorological seasons, the 
corresponding barometrical ranges, and the differences of pressure and range 
between each season, and the general mean of the several seasons. 
The mean annual barometric pressure is 29'381 inches, from which the 
greatest yearly difference in excess is +°084 in., and in defect —109 in. 
In Table XI. is shown the mean monthly and annual pressures as derived 
from the highest and lowest of the pressures at 9 A.M.and 3p.mM. The mean 
annual pressure thus obtained is 29:303 in., differing from the mean of the 
two daily observations by ‘078 in. only. 
In the synoptical Table X XI. the barometric pressure is resolved into its 
gaseous and vapour constituents; and their mean monthly amounts, shown 
for the period of five years, comprised in the dew-point register, namely, from 
1838 to 1842 inclusive, with their respective differences from the several 
annual means :— 
Inches. 
The mean annual gaseous pressure is...... 29°065 
Ditto vapour pressure ...... 0... 026000 ee "324 

Total pressure (from 5 years’ observations)... 29°389 
This result differs from that obtained from the mean of the daily obser- 
vations for eight years by only +-008 in. 
3. Rain (Tables XII. to XV.).—The receiver of the rain-gauge was placed 
38 feet above the ground, and about 470 feet above the mean level of the sea. 
The quantities which fell were registered daily at 9 a.m. The average annual 
amount was 25°258 in. The tables show the distribution of the aggregate 
annual amounts through the several months and meteorological seasons, with 
the differences from the means; and also the number of days on which rain 
fell in each year and season, and their mean monthly and annual numbers. 
The greatest excess in any year above the average amount was in 1839, 
when it amounted to about +3°907 in., and the greatest deficiency in 1844, 
when it amounted to —5:332 in., making a total difference between the two 
years of 9269 in. The mean monthly quantity is 2-105 in., which, on the 
average of eight years, is exceeded in November, February, July, August, 
September, and October, in the order of enumeration, The smallest monthly 
amount falls in April, and next to that month, in December, after which fol- 
low, in order of dryness, March, May and June, 
- The greatest quantities of rain fell in the several seasons in the following 
order, namely, autumn, summer, winter, spring, 

