March iS, 1880] 



NATURE 



479 



Means 

 1861 

 1862 

 1863 

 1864 

 1865 

 1866 

 1867 

 186S 

 1869 

 1S70 

 1871 

 l8 7 2 

 1873 

 1874 

 1875 

 1876 

 1877 

 I878 



Maurilh 



30-071 

 -03S 



- 'O36 

 -•023 

 + "OII 

 + 002 

 -r OIO 



- '004 



- 'OI2 

 + '0I3 



- 'co3 

 + '°3 1 



- - co6 

 + -ooS 

 + "004 

 + '005 

 + •015 



+ - 026 



- 'OIO 



29S7I 



+ ■005 

 + - co6 



+ - 020 

 + 'OII 



-•023 



- - oo9 

 -•020 



- OIO 



- "006 



- 'on 



- "002 



+ ■042 



- X>OI 



29-866 



-018 



-•044 



- 'Oil 



- 023 



- '017 



+ 018 

 + -oiS 

 + ■019 



+ - 037 



- -002 



Colombo. Port Blair. 



29-847 29-804 



+ '029 



+ 'co6 



- -042 



- - oo6 

 -■020 

 -•013 



- 007 



- "006 

 + -oio 

 + •052 



+ 'OIO 



- '020 



- '005 

 + '003 



- 'C04 

 + '002 

 + '037 



With the perhaps doubtful exception of the Mauritius, the 

 general conformity of the oscillation shown by these stations to 

 that of the last cycle of sun-spot frequency is sufficiently obvious, 

 without resorting to any expedient for smoothing the minor 

 variations ; and it is to be noticed that the maximum pressure 

 coincides approximately with the minimum of sun-spots and 

 vice versa. Other registers, such as those of Akyab and Chitta- 

 gong on the Arakan coast, of Calcutta and Bombay (as Mr. 

 F. Chambers has shown), and of Darjiling on the Himalaya 

 exhibit a similar oscillation, but more overlaid with irregular 

 variations apparently, the further we recede from the equator. 

 The registers of Calcutta and Bombay reach back to 1S53 and 

 1847 respectively, and thus comprehend three sun-spot minima, 

 and in the latter case three maxima also. The annual deviation 

 of pressure from the general average at each of these two stations 

 is given in the second and third columns of the following table, 

 and in the fourth and fifth columns the smoothed means obtained 

 by substituting for that of each year the mean of three consecutive 

 years. In the last column are given Wolf's sun-spot numbers up 

 to 1875, taken from the revised table published in vol. xiii. of 

 the Memoirs of the Royal Astronomical Society. 



Both the Calcutta and Bombay registers exhibit oscillations of 

 pressure coinciding approximately with those of the tun-spots, 

 and more pronounced in the case of Bombay than in that of 

 Calcutta. 1 



Hence it may be concluded that throughout the Indo-Malayan 



