464 



Sir N. Lockyer and Dr. W. J. S. Lockyer. [Apr. 13, 



Analysis of Pressure 



Country. 



Station. 



Type. ! Remarks on type. 



Period of 

 observations. 



North Atlantic | Azores 



Las Palmas. 



Russia , 



Siberia 

 China . 



Japan 



St. Petersburg . 



Moscow. . . . 

 Tarchankut 



Lugansk . . 

 Orenbourg 



Catherinbourg . . . 



Arkangel 



Tomsk 



Barnaoul 



Nertchinsk 



Pekin 



Zi-ka-wei 



_ ? 

 _ ? 

 _ P 



_ ? 

 _ ? 



Remarkable, undoubted 

 (-),see Plates 12 and 13 



Difficult to classify 



Hong-Kong (Island). . — Exactly like Cordoba 



Tokio. 

 Kioto 



± ? 

 ± ? 



1874—1903 



1882—1892 



1870—1899 



1870—1899 

 1874—1884 



1872—1899 

 1870—1899 



1870— 1899 



1871— 1899 

 1874—1899 

 1870—1899 

 1870—1899 

 1874—1881 



1874—1884 



1884—1903 



1873—1895 

 1883—1899 



Bombay ( + ) is compared with the Cordoba (-) pressure curve 

 (inverted), and is an example of the adopted types of pressure varia- 

 tion. Iceland is compared with that of the Azores (inverted), and 

 shows the reverse conditions that prevail between a ( + ?) type and 

 (-?)type. 



A fact to which attention was very often drawn in attempting to 

 classify the pressure curves was that some curves after following very 

 closely for many years the Cordoba ( - ) or^Indian ( + ) type of pressure, 

 as the case may be, would revert back to the opposite type for a 

 period of years. Thus to take the case of one station alone, namely, 

 Sydney (Nova Scotia) as an instance, the pressure curve follows very 

 closely that of India from 1875 — 1882, after which up to 1890 it has 

 a very close resemblance to the Cordoba type. The behaviour of this 

 Sydney (Nova Scotia) pressure curve can be compared with the 

 Adelaide (Australia) curve in Plate 13, but it must be noticed that the 

 former has here been inverted. 



There is another important fact which this study has brought to 



