88 RECORD AND DISCUSSION OP ATMOSPHERIC PRESSURE. 



The hourly record of the barometer and attached thermometer readings is given 

 for mean local time, English inches and degrees of Fahrenheit, and for an average 

 elevation of the cistern of the barometer above the mean level of the sea of five 

 feet. 



For the months of September and October, 1853, the barometric and thermo- 

 metric means are not directly comparable with the corresponding figures in 

 Appendix No. XI. of the Narrative (2d vol.) for this reason: In the Appendix the 

 uncorrected aneroid readings are given, while the present abstract contains the 

 corrected or referred readings according to the preceding investigation. After 

 October 23d, the readings of the mercurial barometer take the place of the aneroid 

 readings. 



A star (*) attached to any date in the following record indicates that a corre- 

 sponding remark will be found in the notes appended to the abstract. 



Occasional omissions in the hourly record of either barometer or thermometer 

 readings, as seen by the blanks in the table, have in all cases been supplied by 

 simple interpolations before the means (hourh' or daily) were taken, in order to 

 give the result independent of these omissions. 



