NO. 17.] 



ATMOSPHERIC PRESSURE. 



317 



The barograph stood in the cabin. It was kept going from the 6th July, 

 1893, to the 10th August, 1896. The registrations have been reduced from 

 the 1st August, 1893, to the 31st July, 1896. 



The hourly values of the pressure of the air thus found are given in 

 the following tables for each month from August, 1893, to July, 1896. 



The day is reckoned from midnight to midnight. The tables give the 

 mean pressure of each day as the mean of the 24-hourly values in the hori- 

 zontal rows, and the monthly means for each hour as the means of the 

 numbers in the vertical columns. The mean for the whole month stands as 

 the mean of the numbers in the vertical column headed Mean, or of the 

 numbers in the horizontal row of means. 



The hourly means have been corrected in the usual way 1 for the change 

 due to the variation from the beginning to the end of the month, and reduced 

 to noon in order to render them representative of the true diurnal period. 

 The corrected values are given in the tables as Corr. in the last horizontal 

 row but one. The last horizontal row, headed D. f. m. (Difference from 

 mean) gives the Difference, i. e. hourly corr. mean minus monthly mean, for 

 each of the 24 hours. This series represents the diurnal period of the pres- 

 sure of the air as it is deduced from the observations. 



1 H. WILD. Die Temperaturverhaltnisse des Russischen Reiches. Erste Hfilfte, p. 9. 



