during the Quarter ending March 31, 1850. 361 



The mean daily temperatures of the air till January 24< were 

 below their average values; the mean deficiency was ^°'6. 

 From January 25 to March 1 3 they were above their average 

 values; the mean excess was 5°*8 ; and from March 14< they 

 were below their average values ; and the mean deficiency was 

 6°-2. 



The mean temperature of the air at Greenwich for the three 

 months ending February, constituting the three winter months, 

 was 39°*2; and that of the average from the seventy-nine pre- 

 ceding winters was 37°'6. 



For the month of January was 33°'7, being 2°'0 less than the. 

 average of the seventy-nine preceding years, and 3°"8 less 

 than that of the preceding nine years. 



For the month of February was 'l-4°*7, exceeding that of 

 the average of the preceding seventy-nine years by 6°'5, and 

 exceeding that of the preceding nine years by 5°*1. 



For the month of March was 39°-9, being less than that of 

 the average of seventy-nine years by 1°*0, and less than that 

 of the preceding nine years by 2^'5. 



The mean for the quarter was 39°*4, exceeding the average 

 of seventy-nine years by 1°'2, and less than that of the pre- 

 ceding nine years by 0°"4'. 



The mean temperature of evaporation at Greenisoich — 



For the month of January was 32°*5 ; for February was 

 42°-3; and for March was 37 '0. These values are 4°'4' lesSf 

 S°'0 greater, and 2°"8 less than those of the averages of the 

 same months in the preceding eight years. 



The mean temperature of the detio-point at Greentsoich — 



For the months of January, February and March, were 

 29°- 5, 39°'2 and 32°'7 respectively. These values are 5°-7 

 below, 4<°'l above, and 3°"9 belmx) respectively the averages of 

 the same months in the preceding eight years. The mean 

 value for the quarter was 33°'8, and that for the preceding 

 eight years was 35°'6. 



The mean elastic force of vapour at Greenwich for the quarter 

 was 0"214 inch, being /es5 than the average from the preceding 

 eight years by 0'023 inch. 



The mean weight of water in a cubic foot of air for the 

 quarter was 2*5 grains. The average from the preceding 

 eight years was 2"7 grains. 



The mean degree of humidity in January was 0*897, in Fe- 

 bruary was 0*830, and in March was 0*770. The averages 

 from the eight preceding years were 0*901, 0*886 and 0*836 

 respectively. 



The mean reading of the barometer at Greenwich in January 

 was 29*851' inches, in February was 29*828, and in March was 



Phil. Mag, S. 3. Vol. 36. No. 244-. May 1 850. 2 B 



