the Imperial Academy of Sciences at St Petersburg. 83 



liappened the 3d of January 1826. The smallest height has 

 been 28.35 ; it took place the 6th of February 1825. A parti- 

 cular table has been calculated to ascertain the influence which 

 the moon exercises on the atmosphere ; it contains the means 

 of the barometrical heights observed during the syzygies and 

 the quadratures, that is, the day itself of the syzygy or the 

 quadrature, the two days which precede, and the two which 

 follow it. 



SVZYGIES. 



7 h. a.in. 2 h. p.m. 91]. p.m. 



29.9536 29.9586 29.9646 



The difference between the barometrical height of the sy- 

 zygies and that of the quadratures is so small, that one may, 

 at St Petersburg as at Paris, regard the influence of the 

 moon on the atmospheric tides as nothing. 



Another table which we also insert here, sums up all the ob- 

 servations relative to the influence of each kind of wind on 

 the barometrical height of all the years from 1822 to 1836. 

 This height has been calculated separately for each wind. 



Means, 



Mean, 



29.954 



From this table it appears that, at St Petersburg, the di- 

 rection of the winds has no influence on the mean barome- 

 trical height, and that their effects are completely counter- 

 balanced in the course of the year. Of all the winds, the south- 

 east causes the greatest, the north-west the least, barometri- 

 cal height ; but the absolute maximum takes place during 



