during the Quarter ending June 30, 1848. 189 



inch, which is of the same value as the average of the seven 

 preceding years. 



The mean reading of the barometer at Greenwich for April 

 was 29*589 inches, for May was 29*926 inches, and for June 

 was 29*6-12 inches; these values are 0*164 inch below, 0*158 

 inch above, and 0*167 inch below respectively the averages for 

 the seven preceding years. The mean value for the quarter 

 was 29*719 inches, which is 0*058 inch below the average for 

 these years. 



The mean reading in February was 29*517 inches, in March 

 was 29*505 inches, and in April, as above, 29*589 inches. 

 There is no similar instance in this century of the mean 

 reading of the barometer for any three consecutive months 

 being so small as this; the nearest approach to it was in the 

 •months of November and December, 1803, and January, 1 804. 

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

 temperature, humidity, and pressure, was 531 grains; the 

 average for the seven preceding years was 533 grains. 



The rain fallen at Greenwich in April was 3*4 inches ; in 

 May was 0*4 inch ; and in June was 3*5 inches ; the average 

 values for the seven preceding years were 1*3 inch, 1*6 inch, 

 and 1*5 inch respectively. The amount fallen in the quarter 

 was 7*3 inches, which is 2*9 inches above the average of the 

 corresponding quarters of seven previous years. The total 

 amount fallen in this year till June 30 was 15*2 inches, which 

 is nearly six inches above the average fall in this period as 

 deduced from the above-mentioned years. So large a fall of 

 rain as 7*3 inches has not occurred at the Observatory within 

 the corresponding quarter since the year 1824; and so large 

 a fall as 15 inches within the first six months of the year has 

 not taken place within the previous thirty-three years, — pro- 

 bably not within this century. 



The temperature of the water of the Thames was 60°* 7 by 

 day, and 59°*6 by night. The water, on an average, was 3°*6 

 warmer than the air. 



The horizontal movement of the air was about 114 miles 

 daily, being about its average value. 



The highest and lowest readings of the thermometer in Air at 

 the height of four feet above the ground, and protected as 

 much as possible from the effects of radiation and rain, were 

 80°*0 and 32°*0. 



The average daily range of the readings of the thermometer 

 in Air at the height of four feet, were 16°*7, 30°*5, and 17°*7 

 in the months of April, May, and June respectively. The ave- 

 rage ranges for these months from the observations of the 

 seven preceding years were 1 6°*7, 1 7°*6, and 1 9°*4. The range 



