144 



Anniversary Meeting. 



[Nov. SO, 



attention of magneticians to the probable occurrence of the epoch of max- 

 imum of the magnetic disturbances at the end of the present year 1868, in 

 accordance with the hypothesis of a decennial period, and has noticed 

 the already great increase in the number of days of unusual magnetic 

 disturbance observed at Munich in the months of August, September, 

 and October last. Coincidently with Dr. Lamont's experience in this 

 respect, the continuous records of the magnetometers at Kew have shown 

 larger and more frequent magnetic disturbances than usual; and the 

 Photoheliographs, taken there on all days when the sun is visible, have 

 shown larger and more numerous groups of sun-spots. 



It may be worthy of remark in this connexion, that 1868 is the fourth 

 decennium since the occurrence of the first well-ascertained maximum of 

 magnetic disturbance ; I mean that which, resting on the authority of 

 Arago's admirable and systematic series of observations (1821-1830), has 

 been shown to have taken place in 1828 *. It may be proper, however, 

 to await the more decisive evidence which the years 1873 to 1879 may 

 afford, as to the preference to be given to either of the periods assigned 

 by different magneticians (respectively 10 and Hjy years) as the dura- 

 tion of this remarkable phenomenon, which appears to attest the simul- 

 taneity of physical affections of the sun and of the earth. If the decen- 

 nial hypothesis be correct, 1873 will be the year of minimum, and 1878 

 that of maximum ; if, on the other hand, the period be one of 11 years 

 and a small fraction, 1873 should be the year of maximum, and 1878 the 

 year of minimum ; arid the order of progression and sequence be reversed. 



I mentioned in my last year's Address that the operations of the 

 Bombay Observatory were delayed by the non-reception of the necessary 

 self-recording magnetical and meteorological instruments of the best 

 modern construction. I am glad to be able to state on this occasion that 

 a communication which I ventured to make to Sir Stafford Northcote, 

 Secretary of State for India, had the immediate effect of removing the 

 difficulty which had intervened, and that advice has recently been received 

 of the safe arrival of these instruments at Bombay. We may now con- 

 fidently anticipate that, under the able and zealous superintendence of 

 Mr. Chambers, the Bombay Observatory will speedily take a place in the 

 first rank of institutions specially devoted to these two branches of Phy- 

 sical Science. 



A paper of considerable interest and importance, entitled " Scientific 

 Exploration of Central Australia,' , was presented to the Society in April 

 last. The geographical and scientific researches of its author, Dr. Neu- 

 mayer, published under the authority of the Victorian Government, attest 

 his competency to discuss a subject of this magnitude in its various points 

 of view. The paper itself is an able and interesting one ; it contains the 



* Arago, Meteor. Essays, English Translation. Longman, 1855. Editor's Note, 

 pp. 355-357. 



