366 Mr. J. Glaisher's Remarks on the Weather 



For the month of September was 55°*8, which is2°*3, o, 6, 

 3°-7, 1°*1, and 4°'3 below those of the years 1841, 1842, 1843, 

 1844, and 1847 respectively, 1°*2 and 1°*5 above those of the 

 years 1845 and 1846 respectively; or it is 1°"2 below the ave- 

 rage of these seven years. 



The mean value for the quarter was 58 0, 6; that for 1841 

 was 58°-8 ; for 1842 was 60°'7 ; for 1843 was 60°*8 ; for 1844 

 was 58°-7; for 1845 was 56°-9 ; for 1846 was 62°-6 ; and for 

 1847 was 60 o, 3; so that the defect for this quarter below the 

 corresponding quarter in the years 1841, 1842, 1843, 1844, 

 1846, and 1847, was 0°-2, 2°'l, 2°-2, 0°'l, 4°-0, and 1°*7 re- 

 spectively ; the only year between 1841 and 1847 whose mean 

 temperature for this period was less than that for the present 

 year was 1845, and the difference is 1 0, 7. The average value 

 for this quarter from the seven preceding years was 59°*8 ; 

 so that the mean temperature of the air for the quarter ending 

 September 30, 1848, was below that of the corresponding 

 quarter in the preceding seven years by 1°'2. 



The mean temperature of evaporation at Greenwich — 



For the month of July was 57 0, 6, which is o, l above 

 that for the preceding seven years ; 



For the month of August was 55°'2, which is 2°*9 below 

 that for the preceding seven years; 



For the month of September was 53 0, 2, which is l 0, 5 below 

 that for the preceding seven years. 



The mean value for the quarter was 55°*3, which is 1°*4 

 below the average for the seven preceding years. 



The mean temperature of the dew-point at Greenwich — 



For the month of April was 54°*6, which is 3 o, 0, l°-4, o, 2, 

 l°-9, and l°-8 below those for the years 1841, 1842, 1845, 1846, 

 and 1847 respectively, 1 0, 7 and o, l above those for the years 

 1 843 and 1 844 respectively ; or it is o, 9 above the average of 

 these seven years ; 



For the month of August was 52°'8, which is 2°*2, 6°'l, 

 5°-0, 4°-7, and 3°-3 below those for the years 1841, 1842, 

 1843, 1846, and 1847 respectively, 0°'5 and 0°'2 above those 

 for the years 1844 and 1845 ; or it is 2°*9 below the average for 

 these seven years ; 



For the month of September was 50°* 9, which is 2°*8, 2°-6, 

 4°-0, 2°-3, and 4 o, below those for the years 1841, 1842, 

 1843, 1844, and 1846 respectively, 1°*2 above those of the 

 years 1845 and 1847; or it is 1 0, 9 below the average of these 

 seven years. 



The mean value for the quarter was 52 0, 8, which is 1 0, 3 

 below the average for the corresponding period of the preceding 

 seven years. 



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



