during the Quarter endhig March 31, 184-9. 369 



The reading for the month of February, exceeding 30*1 

 inches at the height of 160 feet, is very remarkable. Since 

 the year 1774- there have been eight such instances only: 

 these occurred in July 1800, April 1801, November 1805, 

 April 1817, February 1821, January 1825, December 1834-, 

 and December 184'3. 



The average weight of a cubic foot of air under the average 

 temperature, humidity, and pressure, was 54-9 grains; the 

 average for the seven preceding years was 546 grains. 



The rain fallen at Greenwich in January was 1"6 inch; in 

 February was 2*2 inches; and in March was 0*5 inch. The 

 amount for the quarter was 4'*24 inches. The average amount 

 for the preceding eight years was 5* 14 inches. 



The temperature of the water of the Thames was 43°'8 by 

 day, and 42^*1 by night. The water, on an average, was 1° 

 warmer than the air. 



The direction of the wind at Greenwich from January 1 to 6 

 was N.E. ; from January 7 to 28 was S.W. ; on January 29 

 was N.N.W. ; from January 30 to March 7 was at times 

 variable, but chiefly S.W. ; from March 8 to 17 was mostly 

 N.W. ; from March 18 to 28 was chiefly N.E. ; and after- 

 wards it was mostly S.S.VV. to the end of the month. 



At Leicester the direction of the wind was S.W. during 

 seventy-six days within the quarter. 



The daily horizontal movement of the air from January 1 to 

 6 was about 90 miles; the greatest value was 200 miles; from 

 January 7 to 28 was 240 miles; the greatest was 500 miles; 

 and from January 30 to March 28 it was 110 miles ; the great- 

 est was 320 miles. The movement of the air in the month of 

 March was small. 



The average daily ranges of the thermometer in air at the 

 height of four feet, were 10°*8 in January, 12^*9 in February, 

 and 13°*8 in March. The average ranges for these three 

 months, from the observations of the eight preceding years, 

 were 8°'l, 9°-6, and 13°-4 respectively. 



2"he readings of the thermometer on grass in January were 

 below 20° on three nights, the lowest was 17^; at and below 

 32° on fourteen nights ; between 32° and 40° on six nights ; 

 above 40° on six nights ; and on one night it was 50°. 



In February the lowest reading was 20°, and the readings 

 were below 32° on eleven nights; between 32° and 40° on eight 

 nights, and above 40° on seven nights. In March the lowest 

 reading was 21° ; and the readings were below 32° on sixteen 

 nights ; between 32 and 40° on twelve nights ; and above 40 

 on three nights. 



The mean amount of cloud was 7'5, being the same as the 

 average for the preceding eight years. 



Phil. Mag. S. 3. Vol. 34. No. 230. May 1849. 2 B 



