during the Qtiarter ending June 30, ISiO. 139 



The mean temperature of evaporation at Greenwich — 



For the month of April was \l°'5 ; for May was 49'''0; and 

 for June was 48°-7. These values are 2='-6, 1^-7 and 6°'7 belou\ 

 respectively, the averages of the same months in the prece- 

 ding eight years. 



The mean value for the quarter was 46°*4, which is 3°'6 

 belo-d) the average of corresponding quarters of eight years. 



The mean temperature of the dew-point at Greenwich — 



For the months of April, May and June, were 39°'l, 43'''9, 

 and 48°'4 respectively. These values are l°-8, 3°-9 and 4°-0 

 beloiso, respectively, the averages of the same months in the 

 preceding eight years. 



The mean value for the quarter was 43°*8, which is 3°*2 

 below the average from the preceding eight years. 



The mean elastic force of vapour for the quarter was 342 

 inch, which is 0*038 hich less than the average for the pre- 

 ceding eight years. 



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

 quarter was 3*5 grains, which is 0*3 grain less than the average 

 for the preceding eight years. 



The mean additional weight of water required to saturate a 

 cubic foot of air was 1*2 grain. 



This value for the preceding eight years was I'l grain. 



The mean degree of humidity in April was 0'864, in May 

 was 0*703, and in March was 0*7 15. The averages for the 

 eight preceding years were 0*802, 0*797, and 0*778. 



The mean readiiig of the barometer at Greenwich in January 

 was 29517 inches, in February was 29*766 inches, and in 

 March was 29*868 inches. These values are respectively 0*215 

 inch less, 0*022 inch less, and 0080 inch greater than the 

 averages of the same montiis for the preceding eight years. 



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

 temperature, humidity and pressure, was 534 grains ; the 

 average for the eight preceding years was 535*4 grains. 



The rain fallen at Greenwich in April was 2*2 inches; in 

 May was 3*9 inches; and in June was 0*2 inch. The amount 

 for the quarter was 6*3 inches ; the average amount for the 

 preceding eight years was 4*74 inches. This excess of rain 

 was experienced only in the southern part of England. The 

 fall of rain between the latitudes of 52° and 53° was about the 

 average for this parallel. North of 53° the fall has been 

 small, and but little more than half the usual amount. 



The horizontal movement of the air has been less than usual ; 

 its direction is uncertain ; observers in the same locality have 

 deduced the average direction differently*. 



* Within ihc last few weeks a system of daily returns of the direction 

 of the wind, taken simultaneously at many different places in England, the 



