Daniell on Meteorological Observations. 103 



to, but which I am inclined to think may have much influence 

 upon the general question. The first column contains the mean 

 temperature, as usually estimated ; the second and third, the 

 mean highest and lowest ; the fourth, the temperature at night, 

 on the earth's surface, of such substances as are best fitted for 

 radiation ; the fifth the mean temperature of similar bodies 

 exposed to the full influence of the sun's rays. This last is 

 only complete for three quarters of a year, the idea having 

 occurred to me last winter. My motives for adopting it I shall 

 presently explain. The sixth column registers the mean con- 

 stituent temperature of the vapour, and the seventh, the same 

 corrected for a night observation as before explained. The 

 extremes of all are included in small figures under their respec- 

 tive columns. 



I shall divide the remarks I have to offer upon these par- 

 ticulars into two parts; the first shall include such observations 

 as regard general consequences from the whole series, and 

 the second shall consist of a short comparison of the several 

 particulars of the two years. 



The total weight of the atmosphere, and the grand problem 

 of the variations of the barometer, are the first things that 

 require our attention, and here it is worthy of remark, that 

 no connexion can be traced between these fluctuations and the 

 variations of the vapour. The barometer, in the last half quarter 

 of the winter, when the pressure of the vapour is least, averages 

 considerably higher than in the last half quarter of the summer, 

 when the same pressure is greatest. A very cursory exami- 

 nation of the first and second columns of Table 2 will furnish 

 plenty of instances of the like discrepancy. This result was 

 certainly contrary to my expectations. Mr. Howard has in- 

 ferred from his admirable system of averages, that " the winter 

 barometer gains in its average .021 inches upon the autumnal ; 

 the vernal .030 inches or half as much more upon the winter ; 

 the summer .045 inches or half as much more still upon the 

 vernal ; but in the autumnal average, the whole difference is 

 lust again, and the barometer comes back to its lowest level." 

 J a rcaboning upon this gradation he ascribes the loss and gain 



