414 M. Neumayer on the Lanar-diurnal Variation [March 28, 



impression is that the changes of pressure at Oxford were followed by 

 similar changes at Kew, only nearly an hour later. 



It is premature (until we obtain more information) to enter into a 

 discussion of the rate of progress of storms ; but we are quite justified in 

 considering the barograph an instrument extremely well adapted to ex- 

 tend our knowledge of atmospheric disturbances. 



We see that on those very occasions when this knowledge is most 

 interesting the barograph comes forward to our assistance, and presents us 

 with results which could not possibly be obtained otherwise than by a 

 system of continuous registration. It does not, however, follow that, while 

 a continuous record is by far the best, other records are of no value ; for 

 should an observer be placed beside an ordinary barometer during the 

 crisis of a storm, observations made in rapid succession and accurately 

 timed would be of very great assistance. Such an observer would in fact 

 produce approximately a record similar in kind to that of a barograph, 

 although inferior in value. 



It ought here to be noticed that two stations are not enough to enable 

 us to determine either the direction in which an atmospheric disturbance 

 is propagated or the rate of propagation. It is only on the improbable 

 supposition that all such disturbances travel in a direct line from Oxford 

 to Kew that barographs at these two places might be deemed enough. In 

 order to obtain the greatest amount of information which such instruments 

 are capable of affording, it is evidently necessary to multiply our stations 

 and to distribute them judiciously over the surface of the country. Nor is 

 it desirable to confine ourselves to one meteorological element, but the 

 barograph should be accompanied by a thermograph and a self-registering 

 anemometer. As this is the system about to be pursued by the Board of 

 Trade in their chief meteorological stations in the British Isles, we may 

 reasonably hope that before long we may by this means receive a large 

 accession to our knowledge of the laws which regulate atmospheric dis- 

 turbances. 



11. " On the Lunar-diurnal Variation of the Magnetic Declination, 

 with special regard to the Moon's Declination.'^ By G. Neu- 

 mayer. Communicated by the President. Received March 11, 

 1867. 



(Abstract.) 



The hourly records of the magnetic declination systematically kept at 

 the Flagstaff Observatory at Melbourne, Victoria, during the period from 

 the 1st of May 1858 to the 28th of February 1863, have been discussed 

 by the author, with a view to determine the lunar-diurnal variation to which 

 that magnetic element is subject. The results arrived at in the course of 

 this discussion elicit, he beheves, facts hitherto unnoticed, to which it 

 seems desirable that the attention of scientific men should be directed. 



