374 Mr. J. Glaisher on the Meteorology of England 



The mean temperature of the dew-point at Greenwich — 



For the months of July, August and September, were 55°'8, 

 53°*1, and 47°*7 respectively. These values are 1°*5 greater, 

 2°*0 less, and 4°*7 less respectively than the averages of the 

 same months in the preceding nine years. 



The mean elastic force of vapour at Greenwich for the quarter 

 was 0*422 inch, being less than the average from the preceding- 

 nine years by 0*008 inch. 



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

 quarter was 4*8 grains, being of the same value as the average 

 from the preceding nine years. 



The mean degree of humidity in July was 0*88, in August 

 was 0*81, and in September was 0*75. The averages from 

 the nine preceding years were 0*79, 0*83 and 0*85 respectively. 



The mean reading of the barometer at Greenwich in July 

 was 29*789 inches, in August was 29* 787, and in September was 

 29*930. These readings are 0*010 less, of the same value, 

 and 0*121 greater respectively than the averages of the same 

 months in the preceding nine years. 



The average weight of a cubic foot of air in the quarter 

 was 527 grains ; exceeding that of the average of the preceding 

 nine years by 1 grain. 



The rain fallen at Greenwich in July was 2*9 inches, in 

 August was 4*9, and in September was 1*3. The falls for the 

 three months on an average of nine years, are 2*3, 2*6, and 2*3 

 inches respectively. 



The average daily ranges of the readings of the thermometer 

 in air at the height of four feet above the soil, in July was 

 20°*0, in August was 18°*6, and in September was 17°*1. 

 The averages for the three months from the preceding nine 

 years were 19°*4, 17°* 6 and 18°*9 respectively. 



The minimum readings of the thermometer on grass, with its 

 bulb fully exposed to the sky, in July was at or below 40° on 

 eight nights; the lowest was 34°, and was above 40° on 

 twenty-three nights ; the highest reading was 55°*5 In 

 August the readings were at and below 32° on two nights ; 

 the lowest reading was 26°; between 32° and 40° on six 

 nights, and above 40° on twenty-three nights; the highest 

 reading was 58°. In September the readings were at or 

 below 32° on nine nights; the lowest reading was 24°; be- 

 tween 32° and 40° on six nights, and above 40° on fifteen 

 nights ; and the highest reading was 50°. 



Thunder-storms occurred on July 2 at Liverpool ; on the 

 4th at Uckfield and Nottingham ; on the 9th at Uckfleld ; on 

 the 15th at Oxford, Aylesbury, Hartwell House,, Hartwell 

 Rectory, Stone, Holkham, Norwich and Oxford ; on the 16th 



