1820.] Mr. Hanson's MeteorologicalJournalfor Manchester. 425 



The annual mean pressure of the atmosphere is 29'G8 inches: 

 highest, 30-34, which was on Jan. 1, and on Sept. 21 ; lowest, 

 28*7(), which occurred on Jan. 15; ditierence of these extremes, 

 1*58 inch, which is considerably below the usual range. The 

 mean daily curve of the atmospherical oscillations, as shown hv 

 the barometrical surface, measures a little more than 37 inches^ 

 Total number of changes, IK). 



The annual mean temperature is nearly 51°; the mean of the 

 first three months, 42-9°; second, 55-4° ; third, 62-4°; fourth, 

 42*1°: of the six winter months, 42-5°; six summer months, 

 58-9°. The maximum of 80° occurred on July 30 ; and the 

 minimum of 20° on Dec. 10. Difference of the extremes, 60°. 



The fall of rain, hail, snow, and sleet, which have fallen in and 

 about Manchester is a trifle more than 35 inches. The greatest 

 quantities of rain fell in January, February, October, and Decem- 

 ber; and the least in May. The notations in the above rain 

 column for November and December have been furnished me 

 bv my friend Mr. John Dalton. My observations in those 

 months were incorrect, in consequence of the frost breaking the 

 bottle in tlie early part of November. A similar accident hap- 

 pened in December. Mr. Dalton makes the annual fall of rain, 

 &c. 35"240 inches. Total number of wet days on which rain fell 

 more or less, 215 ; out of this number, 48 may be designated 

 completely wet. 



The south-v/est, south-east, and north-west, have been the 

 pi'evailing winds. Strong or boisterous winds have rarely occur- 

 red ; out of nine instances on which brisk winds were noted, 

 eight blew in the first four months of the year. The only bois- 

 terous winds of the year occurred in January, viz. on the 17th, 

 18th, and 2oth, from the west and south-west. Snow iias fallen 

 on 25 days, and hail on 14 days. 



The reporter has only noted live instances of thunder, viz. one 

 in May, two in June, one in July, and one in October. 



The temperature of the past year has been generally above an 

 average, although not marked with any great elevations or 

 depressions. The following will show the comparative difference 

 between the monthly means of the past year, and the general 

 monthly means of the 12 preceding years. 



J.'iii. I'VI). M:ir. A!)r. INIar 



Twelve years' general monthly mean 36-0 40-0 41-5 40-4 53-5 

 Monthly means in 1819 4r8 4M 45-5 50-5 56-2 



"DifFereace p. 5-2 p. 1-4 p.4-0 p.4-1 p.2-7 



Jaiir. .Tilly. Aiij;. Sept. Orl. Nov. Der. 



m-o 61-4 6"0-0 56-0 50-0 42-G 37-G 

 59-5 64-2 G5-8 57-1 50-1 40-6 35-5 



p.1-0 p.2-8 p.5-8 p.M p. 1-U m.2jiu.2-i 



