472 



Dr. C. Davison on the Dii 



Barometric 

 Pressure. 



1st comp. 

 (24 hours). 



2nd comp. 

 (12 hours). 



3rd comp. 

 (8 hours). 



4th comp. 

 (6 hours). 



Am pi. 

 mm. 



Epoch, 

 h m 



Am pi. 

 mm. 



Epoch, 

 h m 



Am pi. 

 mm. 



Epoch. 

 h m 



Am pi. 

 mm. 



Epoch, 

 h m 



Tokio (whole year) . 



•52 



A.M. 



1 22 



•54 



A.M. 



9 5 



07 



A.M. 



2 43 



•03 



A.M. 



3 37 



,, (winter) 



•67 



54 



•61 



8 56 



•19 



1 25 



•03 



3 57 



„ (summer) ... 



*41 



2 2 



•48 



9 22 



•03 



5 22 



■01 



3 



Milan (whole year) . 



•18 



3 7 



•36 



9 59 



•01 



2 40 



... 





Naples „ „ 



•09 



57 



•31 



10 13 



•03 



2 18 



•01 



3 9 



Turin „ „ 



•25 



2 3 



■39 



9 59 



•04 



1 34 



•02 



3 34 



Wind- Velocity. 



1st comp. 

 (24 hours). 



2nd comp. 

 (12 hours). 



3rd oomp. 

 (8 hours). 



4th comp. 

 (6 hours). 



Ampl. 

 m. 



Epoch. 



Ampl. 

 m. 



Epoch. 



Ampl. 

 m. 



Epoch. 



Ampl. 

 m. 



Epoch. 





per sec. 



h m 



per sec. 



h m 



per sec. 



h m 



per sec. 



h m 



Tokio (whole year) . 



•86 



P.M. 



42 



•24 



A.M. 



1 52 



•02 



6 23 



•05 



3 48 



„ (winter) 



•48 



11 56 



•25 



1 7 



•04 



5 23 



•06 



3 34 



„ (summer) ... 



125 



59 



•26 



2 35 



•03 



25 



•40 



4 6 



Manila (whole year) 



201 



44 



•51 



1 50 



•06 



1 49 



•08 



3 53 



In the case of wind-velocity the agreement in epoch is 

 much closer, especially for the third and fourth components 

 at Tokio. The epochs of the first and second seismic com- 

 ponents at the same place, however, precede those of wind- 

 velocity by as much as two or three hours. At Manila 

 the epoch of the first component of seismic frequency precedes 

 that of wind-velocity by about two hours, and the epoch of the 

 second component of the former follows that of the latter by 

 half-an-hour. 



The diurnal variation of barometric gradient between Tokio 

 and Nagano (112 miles W. 30° N. of Tokio) seems too slight 

 to produce such important effects, though the epochs of its 

 harmonic components do not differ widely from those of wind- 

 velocity *. 



* I am indebted to Prof. Omori for copies of the tables of the hourly 

 means of barometric pressure at Tokio and Nagano published by the 



